SEARCH · PubMed Health

Results for “PHOSPHOTRANSFERASES”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16Linked to original sources

PubMed1984

Properties of ATP-dependent protein kinase from Streptococcus pyogenes that phosphorylates a seryl residue in HPr, a phosphocarrier protein of the phosphotransferase system.

Transport of sugars across the cytoplasmic membranes of gram-positive bacteria appears to be regulated by the action of a metabolite-activated, ATP-dependent protein kinase that phosphorylates a seryl residue in the phosphocarrier protein of the phosphotransferase system, HPr. We have developed a quantitative assay for measuring the activity of this enzyme from Streptococcus pyogenes. The product of the in vitro protein kinase-catalyzed reaction was shown to be phosphoseryl-HPr by several independent criteria (rates of hydrolysis in the presence of various agents, detection of serine-phosphate in acid hydrolysates, immunological assay, and electrophoretic migration rates). HPrs isolated from four different gram-positive bacteria (S. pyogenes, Streptococcus faecalis, Staphylococcus aureus, and Bacillus subtilis) were shown to be phosphorylated by the kinase from S. pyogenes. In contrast, Escherichia coli HPr was not a substrate of this enzyme. The soluble kinase released from the particulate fraction of the cells with high salt in the presence of a protease inhibitor was shown to have an approximate molecular weight of 60,000 as estimated by gel filtration. Its activity was dependent on divalent cations, with Mg2+ and Mn2+ being most active. EDTA, Pi, and high concentrations of salt were strongly inhibitory. The enzyme was optimally active at pH 7.0, exhibited high affinity for its substrates, and was dependent on the presence of one of several metabolites. Of these compounds, fructose 1-6-diphosphate was most active, with gluconate 6-phosphate, 2-phosphoglycerate, 2,3-diphosphoglycerate, phosphoenolpyruvate, and pyruvate exhibiting moderate to low stimulatory activities. Other compounds tested, including a variety of sugar phosphates, pyridine nucleotides, and other metabolites were without effect. The ATP-dependent phosphorylation of HPr on the seryl residue was strongly inhibited by phosphoenolpyruvate-dependent phosphorylation of the active histidyl residue of this protein. Treatment of the kinase with diethyl pyrocarbonate strongly inhibited the ATP-dependent phosphorylation activity, although the sulfhydryl reagents N-ethylmaleimide, p-chloromercuribenzoate, and iodoacetate were without effect. These results serve to characterize the HPr (serine) kinase, which apparently regulates the rates of carbohydrate transport in streptococcal cells via the phosphotransferase system. A primary role of this kinase in the control of cellular inducer levels and carbohydrate metabolic rates is proposed.

Bacterial Proteins↗

PubMed1984

Identification of a phosphoenolpyruvate:fructose 1-phosphotransferase system in Azospirillum brasilense.

An inducible phosphoenolpyruvate:fructose phosphotransferase system has been detected in Azospirillum brasilense, which requires a minimum of two components of the crude extracts for activity: (i) a soluble fraction (enzyme I) and (ii) a membrane fraction (enzyme II). The uninduced cells neither show any uptake of fructose nor express activity of either of these two enzyme fractions. C-1 of fructose is the site of phosphorylation. This phosphotransferase system does not accept glucose as a substrate for phosphorylation.

Enzyme Induction↗

PubMed1985

Identification of the phosphocarrier protein enzyme IIIgut: essential component of the glucitol phosphotransferase system in Salmonella typhimurium.

The phosphoenolpyruvate-dependent phosphorylation of glucitol has been shown to require four distinct proteins in Salmonella typhimurium: two general energy-coupling proteins, enzyme I and HPr, and two glucitol-specific proteins, enzyme IIgut and enzyme IIIgut. The enzyme IIgut was solubilized from the membrane and purified about 100-fold, free of the other protein constituents of the phosphotransferase system. Enzyme IIIgut was found in both the soluble and the membrane fractions. The soluble enzyme IIIgut was purified to near homogeneity by gel filtration, hydroxylapatite chromatography, and hydrophobic chromatography on butylagarose. It was sensitive to parital inactivation by trypsin and N-ethylmaleimide, but was stable at 80 degrees C. The protein had an approximate molecular weight of 15,000. It was phosphorylated in the presence of phosphoenolpyruvate, enzyme I, and HPr, and this phosphoprotein was dephosphorylated in the presence of enzyme IIgut and glucitol. Antibodies were raised against enzyme IIIgut. Enzyme IIIglc and enzyme IIIgut exhibited no enzymatic or immunological cross-reactivity. Enzyme IIgut, enzyme IIIgut, and glucitol phosphate dehydrogenase activities were specifically induced by growth in the presence of glucitol. These results serve to characterize the glucitol-specific proteins of the phosphotransferase system in S. typhimurium.

Escherichia coli Proteins↗

PubMed1985

Evidence for covalently cross-linked dimers and trimers of enzyme I of the Escherichia coli phosphotransferase system.

Enzyme I of the bacterial phosphotransferase system catalyzes transfer of the phosphoryl moiety from phosphoenolpyruvate to both of the heat-stable phosphoryl carrier proteins of the phosphotransferase system, HPr and FPr. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and high-pressure liquid chromatography, we demonstrated the existence of covalently cross-linked enzyme I dimers and trimers. Enzyme I exchange assays and phosphorylation experiments with [32P]phosphoenolpyruvate showed that covalent dimers and trimers are catalytically active. Inhibitors of the enzyme I-catalyzed phosphoenolpyruvate-pyruvate exchange block the phosphorylation of enzyme I dimers and trimers. Inhibition of the activity of enzyme I by N-ethylmaleimide, but not that by p-chloromercuriphenylsulfonate, could be overcome by high concentrations of enzyme, suggesting that N-ethylmaleimide modification changes the associative properties of enzyme I. We present evidence for two distinct classes of sulfhydryl groups in enzyme I.

Chromatography, High Pressure Liquid↗

PubMed1985

Regulation of cyclic AMP synthesis by enzyme IIIGlc of the phosphoenolpyruvate:sugar phosphotransferase system in crp strains of Salmonella typhimurium.

We investigated the claim (J. Daniel, J. Bacteriol. 157:940-941, 1984) that nonphosphorylated enzyme IIIGlc of the phosphoenolpyruvate:sugar phosphotransferase system is required for full synthesis of bacterial cyclic AMP (cAMP). In crp strains of Salmonella typhimurium, cAMP synthesis by intact cells was regulated by the phosphorylation state of enzyme IIIGlc. Introduction of either a pstHI deletion mutation or a crr::Tn10 mutation resulted in a low level of cAMP synthesis. In contrast, crp strains containing a leaky pstI mutation exhibited a high level of cAMP synthesis which was inhibited by phosphotransferase system carbohydrates. From these results, we conclude that phosphorylated enzyme IIIGlc rather than nonphosphorylated enzyme IIIGlc is required for full cAMP synthesis.

Cyclic AMP↗

PubMed1987

Indirect role of adenylate cyclase and cyclic AMP in chemotaxis to phosphotransferase system carbohydrates in Escherichia coli K-12.

Most strains of Escherichia coli K-12 lacking the enzyme adenylate cyclase showed normal chemotaxis toward carbohydrates taken up and phosphorylated by the phosphoenolpyruvate-dependent carbohydrate: phosphotransferase system. The normal reaction was observed even in the absence of externally added cyclic adenosine 3',5'-phosphate, provided that the enzyme II chemoreceptors and the flagella were synthesized. In the CA8306 series of strains, however, the cya-854 deletion abolished chemotaxis toward phosphotransferase system carbohydrates even though growth on and transport of these carbohydrates were not affected. This abnormal phenotype was due to the presence of a specific mutation in strain CA8306 which mapped in or close to the crp locus and apparently prevented expression of a hitherto unidentified molecule involved in enzyme II-mediated signal transduction. This molecule is neither a pts protein nor a cyclic adenosine 3',5'-phosphate-binding protein.

Adenylyl Cyclases↗

PubMed1991

Mannitol-specific phosphoenolpyruvate-dependent phosphotransferase system of Enterococcus faecalis: molecular cloning and nucleotide sequences of the enzyme IIIMtl gene and the mannitol-1-phosphate dehydrogenase gene, expression in Escherichia coli, and comparison of the gene products with similar enzymes.

Enzyme IIIMtl is part of the mannitol phosphotransferase system of Enterococcus faecalis. It is phosphorylated in a reaction sequence requiring enzyme I and heat-stable phosphocarrier protein (HPr). The phospho group is transferred from enzyme IIIMtl to enzyme IIMtl, which then catalyzes the uptake and concomitant phosphorylation of mannitol. The internalized mannitol-1-phosphate is oxidized to fructose-6-phosphate by mannitol-1-phosphate dehydrogenase. In this report we describe the cloning of the mtlF and mtlD genes, encoding enzyme IIIMtl and mannitol-1-phosphate dehydrogenase of E. faecalis, by a complementation system designed for cloning of gram-positive phosphotransferase system genes. The complete nucleotide sequences of mtlF, mtlD, and flanking regions were determined. From the gene sequences, the primary translation products are deduced to consist of 145 amino acids (enzyme IIIMtl) and 374 amino acids (mannitol-1-phosphate dehydrogenase). Amino acid sequence comparison confirmed a 41% similarity of E. faecalis enzyme IIIMtl to the hydrophilic enzyme IIIMtl-like portion of enzyme IIMtl of Escherichia coli and 45% similarity to enzyme IIIMtl of Staphylococcus carnosus. The putative N-terminal NAD+ binding domain of mannitol-1-phosphate dehydrogenase of E. faecalis shows a high degree of similarity with the N terminus of E. coli mannitol-1-phosphate dehydrogenase (T. Davis, M. Yamada, M. Elgort, and M. H. Saier, Jr., Mol. Microbiol. 2:405-412, 1988) and the N-terminal part of the translation product of S. carnosus mtlD, which was also determined in this study. There is 40% similarity between the dehydrogenases of E. faecalis and E. coli over the whole length of the enzymes. The organization of mannitol-specific genes in E. faecalis seems to be similar to the organization in S. carnosus. The open reading frame for enzyme IIIMtl E. faecalis is followed by a stem-loop structure, analogous to a typical Rho-independent terminator. We conclude that the mannitol-specific genes are organized in an operon and that the gene order is mtlA orfX mtlF mtlD.

Amino Acid Sequence↗

PubMed1994

Phosphoenolpyruvate-dependent maltose:phosphotransferase activity in Fusobacterium mortiferum ATCC 25557: specificity, inducibility, and product analysis.

Phosphoenolypyruvate-dependent maltose:phosphotransferase activity was induced in cells of Fusobacterium mortiferum ATCC 25557 during growth on maltose. The disaccharide was rapidly metabolized by washed cells maintained under anaerobic conditions, but fermentation ceased immediately upon exposure of the cell suspension to air. Coincidentally, high levels of a phosphorylated derivative accumulated within the cells. Chemical and enzymatic analyses, in conjunction with data from 1H, 13C, and 31P nuclear magnetic resonance spectroscopy, established the structure of the purified compound as 6-O-phosphoryl-alpha-D-glucopyranosyl-(1-4)-D-glucose (maltose 6-phosphate). A method for the preparation of substrate amounts of this commercially unavailable disaccharide phosphate is described. Permeabilized cells of F. mortiferum catalyzed the phosphoenolpyruvate-dependent phosphorylation of maltose under aerobic conditions. However, the hydrolysis of maltose 6-phosphate (to glucose 6-phosphate and glucose) by permeabilized cells or cell-free preparations required either an anaerobic environment or addition of dithiothreitol to aerobic reaction mixtures. The first step in dissimilation of the phosphorylated disaccharide appears to be catalyzed by an oxygen-sensitive maltose 6-phosphate hydrolase. Cells of F. mortiferum, grown previously on maltose, fermented a variety of alpha-linked glucosides, including maltose, turanose, palatinose, maltitol, alpha-methylglucoside, trehalose, and isomaltose. Conversely, cells grown on the separate alpha-glucosides also metabolized maltose. For this anaerobic pathogen, we suggest that the maltose:phosphotransferase and maltose 6-phosphate hydrolase catalyze the phosphorylative translocation and cleavage not only of maltose but also of structurally analogous alpha-linked glucosides.

Aerobiosis↗

PubMed2003

The phosphotransferase system of Streptomyces coelicolor is biased for N-acetylglucosamine metabolism.

Mutation of the crr-ptsI gene locus revealed that Streptomyces coelicolor uses the phosphotransferase system (PTS) for N-acetylglucosamine uptake. crr, ptsI, and ptsH, which encode the three general PTS phosphotransferases, are induced by N-acetylglucosamine but not by other PTS substrates. Thus, the S. coelicolor PTS is biased for N-acetylglucosamine utilization, a novel feature that distinguishes this PTS from others.

Acetylglucosamine↗

PubMed2003

Mutations which uncouple transport and phosphorylation in the D-mannitol phosphotransferase system of Escherichia coli K-12 and Klebsiella pneumoniae 1033-5P14.

Mutants of Escherichia coli K-12 were isolated which lack the normal phosphotransferase system-dependent catabolic pathway for D-mannitol (Mtl). In some mutants the pts genes for the general proteins enzyme I and histidine protein of the phosphoenolpyruvate-dependent carbohydrate phosphotransferase systems were deleted. Other mutants expressed truncated mannitol-specific enzymes II (II(Mtl)) which lacked the IIA(Mtl) or IIBA(Mtl) domain(s), and the mtlA genes originated either from E. coli K-12 or from Klebsiella pneumoniae 1033-5P14. The dalD gene from Klebsiella oxytoca M5a1 was cloned on single-copy plasmids and transformed into the strains described above. This gene encodes an NAD-dependent D-arabinitol dehydrogenase (DalD) which converts D-arabinitol into D-xylulose and also converts D-mannitol into D-fructose. The different strains were used to isolate mutations which allow efficient transport of mannitol through the nonphosphorylated II(Mtl) complexes by selecting for growth on this polyhydric alcohol. More than 40 different mutants were analyzed to determine their ability to grow on mannitol, as well as their ability to bind and transport free mannitol and, after restoration of the missing domain(s), their ability to phosphorylate mannitol. Four mutations were identified (E218A, E218V, H256P, and H256Y); all of these mutations are located in the highly conserved loop 5 of the IIC membrane-bound transporter, and two are located in its GIHE motif. These mutations were found to affect the various functions in different ways. Interestingly, in the presence of all II(Mtl) variants, whether they were in the truncated form or in the complete form, in the phosphorylated form or in the nonphosphorylated form, and in the wild-type form or in the mutated form, growth occurred on the low-affinity analogue D-arabinitol with good efficiency, while only the uncoupled mutated forms transported mannitol at a high rate.

Amino Acid Sequence↗

PubMed1976

Herpesvirus proteins: induction of nucleoside phosphotransferase activity after herpes simplex virus infection.

After herpes simplex virus infection of hamster kidney cells there is an induction of nucleoside phosphotransferase activity which can utilize AMP as phosphate donor. The activity is immunologically specific for the infected cell and is induced concomitantly with the virus-coded pyrimidine deoxynucleoside kinase activity. Phosphotransferase activity is not induced in cells lacking both thymidine and deoxycytidine kinase activity.

Adenosine Monophosphate↗

PubMed1991

Two novel protein-tyrosine kinases, each with a second phosphotransferase-related catalytic domain, define a new class of protein kinase.

The protein-tyrosine kinases (PTKs) are a burgeoning family of proteins, each of which bears a conserved domain of 250 to 300 amino acids capable of phosphorylating substrate proteins on tyrosine residues. We recently exploited the existence of two highly conserved sequence elements within the catalytic domain to generate PTK-specific degenerate oligonucleotide primers (A. F. Wilks, Proc. Natl. Acad. Sci. USA 86:1603-1607, 1989). By application of the polymerase chain reaction, portions of the catalytic domains of several novel PTKs were amplified. We describe here the primary sequence of one of these new PTKs, JAK1 (from Janus kinase), a member of a new class of PTK characterized by the presence of a second phosphotransferase-related domain immediately N terminal to the PTK domain. The second phosphotransferase domain bears all the hallmarks of a protein kinase, although its structure differs significantly from that of the PTK and threonine/serine kinase family members. A second member of this family (JAK2) has been partially characterized and exhibits a similar array of kinase-related domains. JAK1 is a large, widely expressed membrane-associated phosphoprotein of approximately 130,000 Da. The PTK activity of JAK1 has been located in the C-terminal PTK-like domain. The role of the second kinaselike domain is unknown.

Amino Acid Sequence↗

PubMed2004

An esterase gene from Lactobacillus casei cotranscribed with genes encoding a phosphoenolpyruvate:sugar phosphotransferase system and regulated by a LevR-like activator and sigma54 factor.

A new esterase-encoding gene was found in the draft genome sequence of Lactobacillus casei BL23 (CECT5275). It is located in an operon together with genes encoding the EIIA, EIIB, EIIC, and EIID proteins of a mannose class phosphoenolpyruvate:sugar phosphotransferase system. After overproduction in Escherichia coli and purification, the esterase could hydrolyze acetyl sugars, hence the operon was named esu for esterase-sugar uptake genes. Upstream of the genes encoding the EII components (esuABCD) and the esterase (esuE), two genes transcribed in the opposite sense were found which encode a Bacillus subtilis LevR-like transcriptional activator (esuR) and a sigma54-like transcriptional factor (rpoN). As compared with the wild-type strain, elevated fructose phosphorylation was detected in L. casei mutants constitutively expressing the esu operon. However, none of the many sugars tested could induce the esu operon. The fact that EsuE exhibits esterase activity on acetyl sugars suggests that this operon could be involved in the uptake and metabolism of esterified sugars. Expression of the esu operon is similar to that of the B. subtilis lev operon: it contains a -12,-24 consensus promoter typical of sigma54-regulated genes, and EsuR and RpoN are essential for its transcription which is negatively regulated by EIIB(Esu). The esuABCDE transcription unit represents the first sigma54-regulated operon in lactobacilli. Furthermore, replacement of His852 in the phosphoenolpyruvate:sugar phosphotransferase system regulation domain II of EsuR with Ala indicated that the transcription activator function of EsuR is inhibited by EIIB(Esu)-mediated phosphorylation at His852.

DNA-Binding Proteins↗

PubMed2007

The phosphotransferase system of Corynebacterium glutamicum: features of sugar transport and carbon regulation.

In this review, we describe the phosphotransferase system (PTS) of Corynebacterium glutamicum and discuss genes for putative global carbon regulation associated with the PTS. C. glutamicum ATCC 13032 has PTS genes encoding the general phosphotransferases enzyme I, HPr and four enzyme II permeases, specific for glucose, fructose, sucrose and one yet unknown substrate. C. gluamicum has a peculiar sugar transport system involving fructose efflux after hydrolyzing sucrose transported via sucrose EII. Also, in addition to their primary PTS, fructose and glucose are each transported by a second transporter, glucose EII and a non-PTS permease, respectively. Interestingly, C. glutamicum does not show any preference for glucose, and thus co-metabolizes glucose with other sugars or organic acids. Studies on PTS-mediated sugar uptake and its related regulation in C. glutamicum are important because the production yield of lysine and cell growth are dependent on the PTS sugars used as substrates for fermentation. In many bacteria, the PTS is also involved in several regulatory processes. However, the detailed molecular mechanism of global carbon regulation associated with the PTS in this organism has not yet been revealed.

Biological Transport↗

PubMed2005

Analysis of 2'-phosphotransferase (Tpt1p) from Saccharomyces cerevisiae: evidence for a conserved two-step reaction mechanism.

Tpt1p is an essential protein responsible for the 2'-phosphotransferase step of tRNA splicing in Saccharomyces cerevisiae, in which the splice junction 2'-phosphate of ligated tRNA is transferred to NAD to form mature tRNA and ADP-ribose 1''-2'' cyclic phosphate. We showed previously that Tpt1p is a member of a family of functional 2'-phosphotransferases found in eukaryotes, eubacteria, and archaea, that the Escherichia coli protein (KptA) is highly specific for 2'-phosphorylated RNAs despite the lack of obvious natural substrates, and that KptA acts on a trinucleotide substrate through an intermediate in which RNA is ADP-ribosylated at the 2'-phosphate. This mechanism is similar to a proposed mechanism of NAD-dependent histone deacetylases. We present evidence here that this mechanism is conserved in S. cerevisiae, and we identify residues important for the second step of the reaction, during which the intermediate is resolved into products. We examined 21 Tpt1 protein variants mutated in conserved residues or blocks of residues and show that one of them, Tpt1 K69A/R71S protein, accumulates large amounts of intermediate with trinucleotide substrate due to a very slow second step. This intermediate can be trapped on beads when formed with biotin-NAD. We also show that Tpt1 K69A/R71S protein forms an intermediate with the natural ligated tRNA substrate and demonstrate that, as expected, this mutation is lethal in yeast. The high degree of conservation of these residues suggests that the entire Tpt1p family is involved in a similar two-step chemical reaction.

Amino Acid Sequence↗

PubMed1991

Effect of growth conditions on the Streptococcus bovis phosphoenolpyruvate glucose phosphotransferase system.

Four strains of the ruminal bacterium Streptococcus bovis were surveyed for phosphoenolpyruvate (PEP) and ATP-dependent phosphorylation of glucose and the nonmetabolizable glucose analog 2-deoxyglucose. All four strains had high rates of glucose phosphorylation with either phosphoryl donor, but 2-deoxyglucose activity was much higher in the presence of PEP. These results provide evidence for a PEP-dependent glucose phosphotransferase system in these bacteria. Mannose and 2-deoxyglucose inhibited PEP-dependent phosphorylation of glucose by S. bovis JB1 by 50 and 38%, respectively, whereas alpha-methylglucoside had little effect. Mannose was a competitive inhibitor of PEP-dependent phosphorylation of glucose with an inhibition constant of 2.8 mM, and PEP-dependent activity in cells grown in batch culture was optimal at pH 7.2. When S. bovis JB1 was grown in continuous culture, PEP-dependent phosphorylation of glucose and 2-deoxyglucose was highest in cells grown at a dilution rate of .10/h and at low glucose concentrations. Phosphoenolpyruvate-dependent activity was optimum at a growth pH of 5.0 for cells grown in medium that contained less than 6.0 g/liter of glucose. These data indicate that PEP-dependent glucose phosphotransferase system activity can be influenced depending on the growth conditions used to culture S. bovis. Furthermore, these results suggest that environmental conditions within the rumen will affect how glucose is transported by S. bovis.

Adenosine Triphosphate↗

PubMed1976

Nucleoside phosphotransferase from Erwinia herbicola, a new membrane-bound enzyme.

A nucleoside phosphotransferase, which catalyzes the phosphorylation of nucleosides to nucleotides by low energy phosphate esters, has been isolated and purified 500-fold from the membrane fraction of Erwinia herbicola. Its most noteworthy difference from other enzymes of this class is that it is membrane bound and can be isolated and handled only in the presence of a detergent. With a ribonucleoside acceptor, adenosine, the reaction product is exclusively 5'-AMP; with deoxyadenosine, 5'- and 3'-nucleotide products appear in the approximate ratio of 2:1, respectively. The enzyme has no detectable phosphatase activity with the best phosphate donors, 5'-dAMP and 5'-dTMP, and very little with less active donors, such as p-nitrophenyl phosphate. This phosphotransferase should be a useful agent for preparing 5'-nucleotides from unusual synthetic bases.

Adenosine↗

PubMed2001

[Integration and intramolecular transposition of the TnBP3 Bordetella pertussis transposon in the Escherichia coli K-12 cells -- mutant for the phosphoenolpyruvate-dependent phosphotransferase system Hpr protein ].

Integration of a plasmid carrying the TnBP3 transposon of Bordetella pertussis into the chromosome of Escherichia coli and transpositions of the integrated structure within a chromosome in the wild-type and mutant cells ptsH devoid of the major Hpr protein of the phosphoenolpyruvate-dependent phosphotransferase system were studied. When transposed to a new chromosome site, the integrated structure was precisely (or almost precisely) excised from the metY gene sequence, which resulted in restoration of the Met+ phenotype. The integration and transposition events were only observed in the E. coli cells carrying the ptsH+ allele. The ptsH mutations inhibited integration and intramolecular transposition, which were restored after phenotypic or genetic suppression of the ptsH mutation. The intensity of the processes studied were suggested to depend on the integrity of a chain that ensures transferring of the phosphoryl residue by proteins of the phosphotransferase system in E. coli K12. The results obtained indicate that the ptsH mutants of E. coli can serve as the optimal host for cloning of fragments carrying repeated sequences of B. pertussis, which may apply to the repeated sequences of other microorganisms.

Bacterial Proteins↗