PubMed Health⌕ Search

Biomedical subjects

N A Oliver

Publications and source records attributed to N A Oliver.

9 recordsLinked to original sources
PubMed1993

Protective cover cap for implant attachment.

A procedure is described for use of a cast metal cover cap to protect implant prosthesis attachments during finishing and polishing. The cap helps prevent distortion or damage to the implant.

Dental Implants↗
PubMed1986

Computer prediction of peptide maps: assignment of polypeptides to human and mouse mitochondrial DNA genes by analysis of two-dimensional-proteolytic digest gels.

We have prepared a computer program that predicts complete and partial peptide maps from amino acid sequences. The program fragments amino acid sequences at designated cleavage sites and calculates the molecular weight and relative labeling of each peptide. These data are graphed as log molecular weight of the original protein (X-axis) vs. log molecular weight of the component peptides (Y-axis). The program is interactive, permitting adjustment of a number of graphic parameters and alteration of the position of proteins in the first dimension to accommodate aberrations in protein mobility. The program has been used to predict the V8 protease peptide maps of the 13 open reading frames (ORFs) identified in the human and the mouse mitochondrial DNA (mtDNA) sequences. The results were compared to the V8 protease peptide maps obtained for mouse and human mitochondrially synthesized proteins by two-dimensional proteolytic digest gels. A high correlation was observed between the predicted and observed peptide maps. These results suggest the assignment of several proteins to mtDNA genes.

Amino Acid Sequence↗
PubMed1983

Assignment of a polymorphic polypeptide to the human mitochondrial DNA unidentified reading frame 3 gene by a new peptide mapping strategy.

A new method of peptide analysis is presented which allows assignment of unknown proteins to coding regions of genomes which have been sequenced. This approach involves comparison of the molecular weights of peptides generated by partial proteolytic digestion with those predicted for a protein whose primary amino acid sequence is deduced from a corresponding nucleotide sequence. The proteolytic digestions are accomplished in situ in the stacking gel of a two-dimensional polyacrylamide gel system. We have used this system to show that two variant proteins of the human mitochondrial DNA, MV-1 and MV-2, are allelic and encoded by the unidentified reading frame 3 (URF 3) gene. This assignment was supported by sequence analysis of a clone of this mtDNA region from a HeLa cell line which expresses the uncommon variant MV-2. Four nucleotide changes were found in HeLa URF 3, relative to the reported sequence from human placenta. Two of these changes alter the primary amino acid sequence of the encoded protein. It is proposed that one of those amino acid changes may account for the observed molecular weight variation in MV-1 and MV-2 by proteolytic cleavage, conformational change, or secondary modification. We have used this method to also assign a mitochondrially translated protein to URF 6. These are the first assignments of mitochondrially synthesized polypeptides to human URF genes and prove conclusively that at least some of these genes are expressed in human cells.

Amino Acid Sequence↗
PubMed1982

Assignment of an oligomycin-resistance locus to human chromosome 10.

An oligomycin-resistant variant of human fibrosarcoma HT1080 was isolated and characterized as nuclear and codominant. The mutant was stable, was not cross-resistant to respiratory inhibitors, and it contained a mitochondrial ATPase which was less sensitive to oligomycin. Hybrids formed between the human mutant and a mouse cell line expressed the resistance phenotype. By a detailed karyotypic analysis of these hybrids using trypsin-Giemsa banding it was found that resistance to oligomycin correlated with the retention of two human chromosomes 10. The hybrid lines contained only mouse mitochondrial DNA as shown by analyses of mitochondrially synthesized proteins and mitochondrial DNA. The study assigns an ATPase oligomycin-resistance locus to human chromosome 10 and suggests that mouse and human subunits can combine in a functional enzyme complex.

Adenosine Triphosphatases↗
PubMed1982

Assignment of two mitochondrially synthesized polypeptides to human mitochondrial DNA and their use in the study of intracellular mitochondrial interaction.

Two mitochondrially synthesized marker polypeptides, MV-1 and MV-2, were found in human HeLa and HT1080 cells. These were assigned to the mitochondrial DNA in HeLa-HT1080 cybrids and hybrids by demonstrating their linkage to cytoplasmic genetic markers. These markers include mitochondrial DNA restriction site polymorphisms and resistance to chloramphenicol, an inhibitor of mitochondrial protein synthesis. In the absence of chloramphenicol, the expression of MV-1 and MV-2 in cybrids and hybrids was found to be directly proportional to the ratio of the parental mitochondrial DNAs. In the presence of chloramphenicol, the marker polypeptide linked to the chloramphenicol-sensitive mitochondrial DNA continued to be expressed. This demonstrated that resistant and sensitive mitochondrial DNAs can cooperate within a cell for gene expression and that the CAP-resistant allele was dominant or codominant to sensitive. Such cooperation suggests that mitochondrial DNAs can be exchanged between mitochondria.

Cell Line↗