Biomedical subjects

C M Croce

Publications and source records attributed to C M Croce.

At least 91 records · Page 5Linked to original sources

PubMed1999

Exon structure and promoter identification of STIM1 (alias GOK), a human gene causing growth arrest of the human tumor cell lines G401 and RD.

The stromal interaction molecular 1 gene (STIM1) encodes a type I trans-membrane protein of unknown function, which induces growth arrest and degeneration of the human tumor cell lines G401 and RD but not HBL100 and CaLu-6, suggesting a role in the pathogenesis of rhabdomyosarcomas and rhabdoid tumors. Here, we describe the STIM1 genomic organization including the identification of the promoter region. The gene consists of 12 exons that span a region larger than 250 kb between the genes RRM1 and NUP98. Nucleotide sequences of all exon-intron boundaries were determined and oligonucleotide primers for the amplification of individual exons were designed. The promoter region was identified within a 1.8-kb SacI fragment at the 5' end of the gene. In vitro CpG methylation of the promoter region indicated that transcription can be downregulated by this mechanism. The genetic tools developed in the present work will help to determine whether pathogenetic mechanisms that associate STIM1 with tumorigenesis involve mutations in coding sequences and/or promoter, and whether methylation could determine STIM1 transcriptional down-regulation in tumor samples.

Cell Division↗

PubMed1999

Role of FHIT in human cancer.

Through investigation of hemizygous and homozygous deletions in common human cancers, including lung cancer, we have cloned and characterized a gene at chromosome region 3p14.2, FHIT, that is inactivated in epithelial tumors, particularly in tumors resulting from exposure to environmental carcinogens. In some tumors, particularly those associated with environmental carcinogens, alterations in the FHIT gene occur quite early in the development of cancer. In other cancers, Fhit inactivation seems to be a later event, possibly associated with progression to more aggressive neoplasias. Thus, detection of Fhit expression by immunohistochemistry in premalignant and malignant tissues may provide important diagnostic and prognostic information.

Acid Anhydride Hydrolases↗

PubMed1999

Loss of FHIT expression in acute lymphoblastic leukemia.

Loss of expression of the FHIT tumor suppressor gene is common in epithelial malignancies such as lung, kidney, esophageal, gastric, and cervical cancers. To assess the role of FHIT in acute leukemias, we examined 18 primary acute lymphoblastic leukemias (ALLs), 8 ALL-derived cell lines, 7 cell lines from other hematological malignancies, 14 lymphoblastoid cell lines, and 5 peripheral blood lymphocyte samples for expression of FHIT mRNA and protein by reverse transcription-PCR and Northern and Western blots. Fhit protein expression was detected in only 24% of primary ALLs and leukemia/lymphoma cell lines, but it was detected in all lymphoblastoid cell lines and peripheral blood lymphocyte samples. Interestingly, Fhit protein expression was lost in all T-cell ALLs but was lost in only half of the B-cell ALLs. Northern blotting of 7 normal lymphoblastoid cell lines and 13 of the neoplastic cell lines confirmed the results obtained by Western blotting regarding FHIT expression. The high frequency of loss of Fhit expression in ALLs suggests that inactivating alterations at the FHIT locus contribute to development of the leukemias.

Acid Anhydride Hydrolases↗

PubMed1999

Significance of FHIT expression in chronic myelogenous leukemia.

Loss or reduced expression of the fragile histidine triad (FHIT) gene, a tumor suppressor gene localized at chromosome 3p14.2, is common in several solid and hematological cancers and has been associated with tumor progression and worse prognosis. The role of the FHIT gene in the pathogenesis of chronic myelogenous leukemia (CML) or its progression from a chronic phase to the accelerated and blastic phases is not known. The aim of this study was to evaluate whether Fhit protein expression is altered in CML, and whether it plays any role in CML progression, disease responsiveness to therapy, or prognosis. A total of 195 patients with Philadelphia chromosome-positive CML were evaluated, including 129 patients in early chronic phase (time from diagnosis to study, 12 months or less), 30 patients in late chronic phase, and 36 patients in the accelerated and blastic phases. The levels of cellular Fhit protein expression were determined using Western blot analysis and solid-phase RIA and compared to the levels in 31 normal marrows. The median Fhit expression in normal marrows was assigned a value of 1, and the levels in CML samples were normalized to the median of the normal control. Fhit levels in CML samples were evaluated in relation to CML phase and patient characteristics and prognosis in the early chronic phase. The median Fhit value in CML samples was 0.89 (range, 0.34-2.62). Eight of the 195 (4%) CML samples showed Fhit levels <0.5 and lacked detectable Fhit protein by Western blot. There was no difference in the levels of Fhit expression by different CML phases. In early chronic phase, reduced Fhit expression tended to be associated with leukocytosis (P = 0.04) and lower platelet counts (P = 0.01), but not with poorer-risk groups. No differences in response to IFN-alpha therapy or in survival were observed by different Fhit levels. Lack of Fhit protein expression was detected in 4% of CML cases, and reduced expression occurred in a subpopulation of patients. However, reduced Fhit expression is not associated with progression, response to therapy, or prognosis in CML.

Acid Anhydride Hydrolases↗

PubMed1998

Loss of FHIT function in lung cancer and preinvasive bronchial lesions.

We previously cloned and characterized the tumor suppressor gene FHIT (fragile histidine triad) at chromosome 3p14.2 and found that this gene is altered by deletions in human tumors, including lung cancer. To assess the frequency and specificity of inactivation and its relevance in a clinical setting, we have produced antibodies against the Fhit protein and studied its expression in a series of non-small cell lung cancers and normal bronchial mucosa and a spectrum of preinvasive lesions by immunohistochemistry. The data indicate that the loss of Fhit protein is the most frequent alteration in non-small cell lung cancer (73%) and precancerous lesions (93%), is significantly higher in the tumors of smokers (75%) than in those of nonsmokers (39%; P < 0.0005), and is an independent and more frequent event than p53 overexpression in tumors and precancerous lesions (73 versus 46%). The percentage of cases lacking Fhit expression was higher in the squamous type compared to adenocarcinoma (87 versus 57%; P < 0.00001), whereas other histotypes (large cell, mucoepidermal) showed an intermediate value (69%). Loss of Fhit expression in a very high percentage of primary lung carcinomas and precancerous lesions supports the notion that FHIT alterations play an important role in the growth control of bronchial cells. FHIT inactivation is particularly important in squamous cell carcinomas that are often associated with precursor dysplastic lesions. The overall high frequency and precocity of Fhit loss in lung carcinogenesis and the development of the presently described immunohistochemical approach suggest a potential use of this gene in the early detection of lung cancer and in chemopreventive studies as an intermediate biomarker.

Acid Anhydride Hydrolases↗

PubMed1998

Loss of FHIT expression in gastric carcinoma.

Loss of heterozygosity involving the short arm of chromosome 3 has been reported in gastric and other human tumors. We have cloned and mapped a candidate tumor suppressor gene, FHIT (fragile histidine triad), to this chromosomal region (3p14.2). To investigate the role of FHIT gene alterations in the development of gastric carcinoma, we examined 8 gastric carcinoma-derived cell lines and 32 primary adenocarcinoma samples by Southern blot analysis. We also analyzed the integrity of FHIT transcripts by reverse transcription-PCR. The occurrence of alterations in the FHIT gene and its transcript correlated with the absence of Fhit protein expression by immunoblot analysis in the cancer cell lines. Four of eight cell lines showed deletion or rearrangement within the FHIT gene, together with the absence of the wild-type transcript and the Fhit protein. Among the primary gastric carcinomas, rearrangement of the FHIT gene and/or aberrant reverse transcription-PCR products were detected in 17 of 32 (53%) tumors, and 20 of 30 (67%) samples exhibited an absence of Fhit protein expression. Gastric cancer is thought to develop from carcinogenic exposure, possibly explaining the high frequency of abnormalities in the FHIT gene, a fragile locus exhibiting susceptibility to carcinogen-induced alterations. The consequent absence or reduction of Fhit protein expression is consistent with the proposal that the FHIT gene is a preferential target of environmental carcinogens and that FHIT inactivation plays a role in the development of gastric cancer.

Acid Anhydride Hydrolases↗

PubMed1998

Molecular cloning and characterization of ZNF202: a new gene at 11q23.3 encoding testis-specific zinc finger proteins.

Two distinct regions of loss of heterozygosity (LOH) in breast carcinomas were previously identified at chromosome 11q23. With the aim of identifying a tumor suppressor gene, we undertook the isolation and characterization of genes within LOH region 2, defined between loci D11S1345 and D11S1316, which spans an area of about 1 Mb. Here, we describe the cloning and characterization of a new gene, ZNF202. The gene, which spans a genomic area of approximately 10 kb, is almost exclusively expressed in testis as a 4-kb mRNA. The predicted amino acid sequence of the protein product revealed significant homologies with zinc finger proteins, indicating that the ANF202 protein may function as a transcription factor. The presence of multiple CK2 and PKC phosphorylation sites suggests that its activity may be regulated by phosphorylation. The gene is also expressed in breast carcinoma cell lines. However, mutation analysis of 39 breast cancer samples revealed no evidence of mutations, indicating that ZNF202 is unlikely to be involved in the pathogenesis of this neoplasm. Nevertheless, a role for ZNF202 in the tumorigenic process of other tissues cannot be excluded.

Amino Acid Sequence↗

PubMed1998

The murine Fhit locus: isolation, characterization, and expression in normal and tumor cells.

The murine Fhit locus maps near the centromere nu proximal Ptprg locus on mouse chromosome 14. The cDNA sequence and structure are similar to those of the human gene, with exons 5-9 encoding the protein. The predominant mRNA in the tissues and cell lines tested was an alternatively spliced form missing exon 3. Most murine cell lines tested, including lines established from normal mouse embryos and tumors, expressed very low or undetectable levels of Fhit mRNA. Most normal mouse tissues expressed wild-type Fhit mRNA, whereas approximately 40% of murine lung carcinomas expressed wild-type and aberrant Fhit RT-PCR products that lacked various exons. Several tumorigenic mouse cell lines exhibited homozygous deletions of Fhit exons. We conclude that the murine Fhit gene, like its human counterpart, is a target of alterations involved in murine carcinogenesis.

Acid Anhydride Hydrolases↗

PubMed1998

Nitrilase and Fhit homologs are encoded as fusion proteins in Drosophila melanogaster and Caenorhabditis elegans.

The tumor suppressor gene FHIT encompasses the common human chromosomal fragile site at 3p14.2 and numerous cancer cell biallelic deletions. To study Fhit function we cloned and characterized FHIT genes from Drosophila melanogaster and Caenorhabditis elegans. Both genes code for fusion proteins in which the Fhit domain is fused with a novel domain showing homology to bacterial and plant nitrilases; the D. melanogaster fusion protein exhibited diadenosine triphosphate (ApppA) hydrolase activity expected of an authentic Fhit homolog. In human and mouse, the nitrilase homologs and Fhit are encoded by two different genes: FHIT and NIT1, localized on chromosomes 3 and 1 in human, and 14 and 1 in mouse, respectively. We cloned and characterized human and murine NIT1 genes and determined their exon-intron structure, patterns of expression, and alternative processing of their mRNAs. The tissue specificity of expression of murine Fhit and Nit1 genes was nearly identical. Because fusion proteins with dual or triple enzymatic activities have been found to carry out specific steps in a given biochemical or biosynthetic pathway, we postulate that Fhit and Nit1 likewise collaborate in a biochemical or cellular pathway in mammalian cells.

Acid Anhydride Hydrolases↗

PubMed1998

Genetic, biochemical, and crystallographic characterization of Fhit-substrate complexes as the active signaling form of Fhit.

Alterations in the FHIT gene at 3p14.2 occur as early and frequent events in the development of several common human cancers. The ability of human Fhit-negative cells to form tumors in nude mice is suppressed by stable reexpression of Fhit protein. Fhit protein is a diadenosine P1,P3-triphosphate (ApppA) hydrolase whose fungal and animal homologs form a branch of the histidine triad (HIT) superfamily of nucleotide-binding proteins. Because the His-96 --> Asn substitution of Fhit, which retards ApppA hydrolase activity by seven orders of magnitude, did not block tumor-suppressor activity in vivo, we determined whether this mutation affected ApppA binding or particular steps in the ApppA catalytic cycle. Evidence is presented that His-96 --> Asn protein binds ApppA well and forms an enzyme-AMP intermediate extremely poorly, suggesting that Fhit-substrate complexes are the likely signaling form of the enzyme. The cocrystal structure of Fhit bound to Ado-p-CH2-p-ps-Ado (IB2), a nonhydrolyzable ApppA analog, was refined to 3.1 A, and the structure of His-96 --> Asn Fhit with IB2 was refined to 2.6 A, revealing that two ApppA molecules bind per Fhit dimer; identifying two additional adenosine-binding sites on the dimer surface; and illustrating that His-98 is positioned to donate a hydrogen bond to the scissile bridging oxygen of ApppA substrates. The form of Fhit bound to two ApppA substrates would present to the cell a dramatically phosphorylated surface, prominently displaying six phosphate groups and two adenosine moieties in place of a deep cavity lined with histidines, arginines, and glutamines.

Acid Anhydride Hydrolases↗

PubMed1998

Expression of apoptosis-regulating proteins in chronic lymphocytic leukemia: correlations with In vitro and In vivo chemoresponses.

B-cell chronic lymphocytic leukemia (B-CLL) represents a neoplastic disorder caused primarily by defective programmed cell death (PCD), as opposed to increased cell proliferation. Defects in the PCD pathway also contribute to chemoresistance. The expression of several apoptosis-regulating proteins, including the Bcl-2 family proteins Bcl-2, Bcl-XL, Mcl-1, Bax, Bak, and BAD; the Bcl-2-binding protein BAG-1; and the cell death protease Caspase-3 (CPP32), was evaluated by immunoblotting using 58 peripheral blood B-CLL specimens from previously untreated patients. Expression of Bcl-2, Mcl-1, BAG-1, Bax, Bak, and Caspase-3 was commonly found in circulating B-CLL cells, whereas the Bcl-XL and BAD proteins were not present. Higher levels of the anti-apoptotic protein Mcl-1 were strongly correlated with failure to achieve complete remission (CR) after single-agent therapy (fludarabine or chlorambucil) (P = .001), but the presence of only seven CRs among the 42 patients for whom follow-up data were available necessitates cautious interpretation of these observations. Higher levels of the anti-apoptotic protein BAG-1 were also marginally associated with failure to achieve CR (P = .04). Apoptosis-regulating proteins were not associated with patient age, sex, Rai stage, platelet count, hemoglobin (Hb) concentration, or lymph node involvement, although higher levels of Bcl-2 and a high Bcl-2:Bax ratio were correlated with high numbers (>10(5)/microL) of white blood cells (WBC) (P = .01; .007) and higher levels of Bak were weakly associated with loss of allelic heterozygosity at 13q14 (P = .04). On the basis of measurements of apoptosis induction by fludarabine using cultured B-CLL specimens, in vitro chemosensitivity data failed to correlate with in vivo clinical response rates (n = 42) and expression of the various apoptosis-regulating proteins. Although larger prospective studies are required before firm conclusions can be reached, these studies show the expression in B-CLLs of multiple apoptosis-regulating proteins and suggest that the relative levels of some of these, such as Mcl-1, may provide information about in vivo responses to chemotherapy. In vitro chemosensitivity data, however, do not appear to be particularly useful in predicting responses in B-CLL.

Adult↗

PubMed1998

Serine-70 is one of the critical sites for drug-induced Bcl2 phosphorylation in cancer cells.

Taxoids and other microtubule-damaging drugs are known to induce Bcl2 phosphorylation at the G2-M phase of the cell cycle, with concomitant apoptosis in malignant cells derived from a variety of human malignancies, including leukemia, lymphoma, and breast and prostate cancer. We have investigated the ability of another antineoplastic drug, dolastatin 10, in inducing Bcl2 phosphorylation and apoptosis. We also investigated the effects of a phosphatase inhibitor okadaic acid in the regulation of Bcl2 phosphorylation, cell cycle arrest, and programmed cell death. Moreover, site-directed mutagenesis studies were performed to determine the specific serine residue(s) responsible for drug-induced Bcl2 phosphorylation. Our results indicate that these antimicrotubule agents or okadaic acid can induce posttranslational modification (phosphorylation) of Bcl2 protein at multiple serine residues. Interestingly, mutation of a serine residue at position 70 to alanine can significantly decrease drug-induced posttranslational modification (phosphorylation) of Bcl2 protein. Apparently, Ser70 seems to be a critical site for drug-induced posttranslational modification (phosphorylation) of the Bcl2 protein.

Alanine↗

PubMed1998

The C-terminal SET domains of ALL-1 and TRITHORAX interact with the INI1 and SNR1 proteins, components of the SWI/SNF complex.

The ALL-1 gene was discovered by virtue of its involvement in human acute leukemia. Its Drosophila homolog trithorax (trx) is a member of the trx-Polycomb gene family, which maintains correct spatial expression of the Antennapedia and bithorax complexes during embryogenesis. The C-terminal SET domain of ALL-1 and TRITHORAX (TRX) is a 150-aa motif, highly conserved during evolution. We performed yeast two hybrid screening of Drosophila cDNA library and detected interaction between a TRX polypeptide spanning SET and the SNR1 protein. SNR1 is a product of snr1, which is classified as a trx group gene. We found parallel interaction in yeast between the SET domain of ALL-1 and the human homolog of SNR1, INI1 (hSNF5). These results were confirmed by in vitro binding studies and by demonstrating coimmunoprecipitation of the proteins from cultured cells and/or transgenic flies. Epitope-tagged SNR1 was detected at discrete sites on larval salivary gland polytene chromosomes, and these sites colocalized with around one-half of TRX binding sites. Because SNR1 and INI1 are constituents of the SWI/SNF complex, which acts to remodel chromatin and consequently to activate transcription, the interactions we observed suggest a mechanism by which the SWI/SNF complex is recruited to ALL-1/trx targets through physical interactions between the C-terminal domains of ALL-1 and TRX and INI1/SNR1.

Amino Acid Sequence↗

PubMed1998

Identification and characterization of the ARP1 gene, a target for the human acute leukemia ALL1 gene.

ALL1, the human homologue of Drosophila trithorax, is directly involved in human acute leukemias associated with abnormalities at 11q23. Using the differential display method, we isolated a gene that is down-regulated in All1 double-knockout mouse embryonic stem (ES) cells. The gene, designated ARP1 (also termed RIEG, Ptx2, or Otlx2), is a member of a family of homeotic genes containing a short motif shared with several homeobox genes. Using a bacterially synthesized All1 polypeptide encompassing the AT-hook motifs, we identified a 0.5-kb ARP1 DNA fragment that preferentially bound to the polypeptide. Within this DNA, a region of approximately 100 bp was protected by the polypeptide from digestion with ExoIII and DNase I. Whole-mount in situ hybridization to early mouse embryos of 9.5-10.5 days indicated a complex pattern of Arp1 expression spatially overlapping with the expression of All1. Although the ARP1 gene is expressed strongly in bone marrow cells, no transcripts were detected in six leukemia cell lines with 11q23 translocations. These results suggest that ARP1 is up-regulated by the All1 protein, possibly through direct interaction with an upstream DNA sequence of the former. The results are also consistent with the suggestion that ALL1 chimeric proteins resulting from 11q23 abnormalities act in a dominant negative fashion.

Amino Acid Sequence↗

PubMed1998

Crystal structure of MTCP-1: implications for role of TCL-1 and MTCP-1 in T cell malignancies.

Two related oncogenes, TCL-1 and MTCP-1, are overexpressed in T cell prolymphocytic leukemias as a result of chromosomal rearrangements that involve the translocation of one T cell receptor gene to either chromosome 14q32 or Xq28. The crystal structure of human recombinant MTCP-1 protein has been determined at 2.0 A resolution by using multiwavelength anomalous dispersion data from selenomethionine-enriched protein and refined to an R factor of 0.21. MTCP-1 folds into a compact eight-stranded beta barrel structure with a short helix between the fourth and fifth strands. The topology is unique. The structure of TCL-1 has been predicted by molecular modeling based on 40% amino acid sequence identity with MTCP-1. The identical residues are clustered inside the barrel and on the surface at one side of the barrel. The overall structure of MTCP-1 superficially resembles the structures of proteins in the lipocalin family and calycin superfamily. These proteins have diverse functions, including transport of retinol, fatty acids, chromophores, pheromones, synthesis of prostaglandin, immune modulation, and cell regulation. However, MTCP-1 differs in the topology of the beta strands. The structural similarity suggests that MTCP-1 and TCL-1 form a unique family of beta barrel proteins that is predicted to bind small hydrophobic ligands and function in cell regulation.

Amino Acid Sequence↗

PubMed1998

Transcriptional map of 170-kb region at chromosome 11p15.5: identification and mutational analysis of the BWR1A gene reveals the presence of mutations in tumor samples.

Chromosome region 11p15.5 harbors unidentified genes involved in neoplasms and in the genetic disease Beckwith-Wiedemann syndrome. The genetic analysis of a 170-kb region at 11p15.5 between loci D11S601 and D11S679 resulted in the identification of six transcriptional units. Three genes, hNAP2, CDKN1C, and KVLQT1, are well characterized, whereas three genes are novel. The three additional genes were designated BWR1A, BWR1B, and BWR1C. Full-length cDNAs for these three genes were cloned and nucleotide sequences were determined. While our work was in progress, BWR1C cDNA was described as IPL [Qian, N., Franck, D., O'Keefe, D., Dao, D. , Zhao, L., Yuan, L., Wang, Q., Keating, M., Walsh, C. & Tycko, B. (1997) Hum. Mol. Genet. 6, 2021-2029]. The cloning and mapping of these genes together with the fine mapping of the three known genes indicates that the transcriptional map of this region is likely to be complete. Because this region frequently is altered in neoplasms and in the genetic disease Beckwith-Wiedemann syndrome, we carried out a mutational analysis in tumor cell lines and Beckwith-Wiedemann syndrome samples that resulted in the identification of genetic alterations in the BWR1A gene: an insertion that introduced a stop codon in the breast cancer cell line BT549 and a point mutation in the rhabdomyosarcoma cell line TE125-T. These results indicate that BWR1A may play a role in tumorigenesis.

Beckwith-Wiedemann Syndrome↗

PubMed1998

Deregulated expression of TCL1 causes T cell leukemia in mice.

The TCL1 oncogene on human chromosome 14q32.1 is involved in the development of T cell leukemia in humans. These leukemias are classified either as T prolymphocytic leukemias, which occur very late in life, or as T chronic lymphocytic leukemias, which often arise in patients with ataxia telangiectasia (AT) at a young age. The TCL1 oncogene is activated in these leukemias by juxtaposition to the alpha or beta locus of the T cell receptor, caused by chromosomal translocations t(14:14)(q11:q32), t(7:14)(q35:q32), or by inversions inv(14)(q11:q32). To show that transcriptional alteration of TCL1 is causally involved in the generation of T cell neoplasia we have generated transgenic mice that carry the TCL1 gene under the transcriptional control of the p56(lck) promoter element. The lck-TCL1 transgenic mice developed mature T cell leukemias after a long latency period. Younger mice presented preleukemic T cell expansions expressing TCL1, and leukemias developed only at an older age. The phenotype of the murine leukemias is CD4-CD8+, in contrast to human leukemias, which are predominantly CD4+CD8-. These studies demonstrate that transcriptional activation of the TCL1 protooncogene can cause malignant transformation of T lymphocytes, indicating the role of TCL1 in the initiation of malignant transformation in T prolymphocytic leukemias and T chronic lymphocytic leukemias.

Animals↗

PubMed1998

Purification and characterization of recombinant forms of TCL-1 and MTCP-1 proteins.

The TCL-1 gene which is located on chromosome 14 plays a major role in human hematopoeitic malignancies and encodes a 14-kDa protein whose function has not been determined. The TCL-1 gene is expressed in pre-B cells, in immature thymocytes, and at low levels in activated T cells but not in peripheral mature B cells and in normal cells. The TCL-1 protein is similar in its primary structure to a protein encoded by the mature T cell proliferation gene (MTCP-1). The MTCP-1 gene is located on the X chromosome and has been shown to be involved in rare chromosomal translocations in T cell proliferative diseases. The TCL-1 and MTCP-1 genes appear to be members of a family of genes involved in lymphoid proliferation and T cell malignancies. Our laboratory has undertaken the study of the TCL-1 and MTCP-1 proteins to determine the structure and the function of these related proteins. In the present report, we have produced, using a bacterial expression system, both purified TCL-1 and MTCP-1 proteins in forms with and without a six His tag sequence. The recombinant proteins were purified by chromatography on a Ni-NTA resin followed by reverse-phase FPLC using a buffer system at pH 7.9 and a polymeric-based reverse-phase column. The MTCP-1 recombinant proteins display greater solubility, do not form disulfide linked dimers or oligomers, and elute at a lower isopropanol concentration than the corresponding TCL-1 proteins. The purified recombinant TCL-1 and MTCP-1 proteins have been characterized by N-terminal sequence analysis, time of flight mass spectrometry, and circular dichroism spectroscopy. Initial results have indicated that the MTCP-1 protein with the His tag removed is suitable for both NMR and X-ray crystallographic methods of structure determination.

Amino Acid Sequence↗