- SbnI is a free serine kinase that generates O-phospho-L-serine for staphyloferrin B biosynthesis in Staphylococcus aureus
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Staphyloferrin B (SB) is an iron-chelating siderophore produced by Staphylococcus aureus in invasive infections. Proteins for SB biosynthesis and export are encoded by the sbnABCDEFGHI gene cluster, in which SbnI, a member of the ParB/Srx superfamily, acts as a heme-dependent transcriptional regulator of the sbn locus. However, no structural or functional information about SbnI is available. Here, a crystal structure of SbnI revealed striking structural similarity to an ADP-dependent free serine kinase, SerK, from the archaea Thermococcus kodakarensis. We found that features of the active sites are conserved, and biochemical assays and31P NMR and HPLC analyses indicated that SbnI is also a free serine kinase but uses ATP rather than ADP as phosphate donor to generate the SB precursor O-phospho- L-serine (OPS). SbnI consists of two domains, and elevated B-factors in domain II were consistent with the open-close reaction mechanism previously reported for SerK. Mutagenesis of Glu20 and Asp58 in SbnI disclosed that they are required for kinase activity. The only known OPS source in bacteria is through the phosphoserine aminotransferase activity of SerC within the serine biosynthesis pathway, and we demonstrate that an S. aureus serC mutant is a serine auxotroph, consistent with a function in L-serine biosynthesis. However, the serC mutant strain could produce SB when provided L-serine, suggesting that SbnI produces OPS for SB biosynthesis in vivo. These findings indicate that besides transcriptionally regulating the sbn locus, SbnI also has an enzymatic role in the SB biosynthetic pathway.
- Verstraete, Meghan M.,Perez-Borrajero, Cecilia,Brown, Kirstin L.,Heinrichs, David E.,Murphy, Michael E. P.
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- Elucidation of a Self-Sustaining Cycle in Escherichia coli l -Serine Biosynthesis That Results in the Conservation of the Coenzyme, NAD+
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The equilibrium of the reaction catalyzed by d-3-phosphoglycerate dehydrogenase (PGDH), the first enzyme in the l-serine biosynthetic pathway, is far in the direction away from serine synthesis. As such, the enzyme is usually assayed in this direction. To
- Grant, Gregory A.
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- Library Selection with a Randomized Repertoire of (βα)8-Barrel Enzymes Results in Unexpected Induction of Gene Expression
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The potential of the frequently encountered (βα)8-barrel fold to acquire new functions was tested by an approach combining random mutagenesis and selection in vivo. For this purpose, the genes encoding 52 different phosphate-binding (βα)8-barrel proteins were subjected to error-prone PCR and cloned into an expression plasmid. The resulting mixed repertoire was used to transform different auxotrophic Escherichia coli strains, each lacking an enzyme with a phosphate-containing substrate. After plating of the different transformants on minimal medium, growth was observed only for two strains, lacking either the gene for the serine phosphatase SerB or the phosphoserine aminotransferase SerC. The same mutants of the E. coli genes nanE (encoding a putative N-acetylmannosamine-6-phosphate 2-epimerase) and pdxJ (encoding the pyridoxine 5′-phosphate synthase) were responsible for rescuing both ΔserB and ΔserC. Unexpectedly, the complementing NanE and PdxJ variants did not catalyze the SerB or SerC reactions in vitro. Instead, RT-qPCR, RNAseq, and transcriptome analysis showed that they rescue the deletions by enlisting the help of endogenous E. coli enzymes HisB and HisC through exclusive up-regulation of histidine operon transcription. While the promiscuous SerB activity of HisB is well-established, our data indicate that HisC is promiscuous for the SerC reaction, as well. The successful rescue of ΔserB and ΔserC through point mutations and recruitment of additional amino acids in NanE and PdxJ provides another example for the adaptability of the (βα)8-barrel fold.
- Rohweder, Bettina,Lehmann, Gerhard,Eichner, Norbert,Polen, Tino,Rajendran, Chitra,Ruperti, Fabian,Linde, Mona,Treiber, Thomas,Jung, Oona,Dettmer, Katja,Meister, Gunter,Bott, Michael,Gronwald, Wolfram,Sterner, Reinhard
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p. 4207 - 4217
(2019/10/17)
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- Peptide Tyrosinase Activators
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Peptides that increase melanin synthesis are provided. These peptides include pentapeptides YSSWY, YRSRK, and their variants. The peptides may activate the enzymatic activity of tyrosinase to increase melanin synthesis. The pharmaceutical, cosmetic, and other compositions including the peptides are also provided. The methods of increasing melanin production in epidermis of a subject are provided where the methods include administering compositions comprising an amount of one or more peptides effective to increase the melanin production. The methods also include treating vitiligo or other hypopigmentation disorders with compositions including one or more peptides.
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- Metal Nanoparticles
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A metal nanoparticle-phosphopeptide complex comprising a metal nanoparticle and a phosphopeptide is provided. The phosphopeptide comprises two or more contiguous peptide motifs and two or more phosphorus-containing groups capable of interacting with the surface of the metal nanoparticle. The amino acids at the equivalent position in each peptide motif have similar structural and/or electronic properties. Each phosphorus-containing group is bound to an amino acid in the two or more contiguous peptide motifs. Methods for preparing the metal nanoparticle-phosphopeptide complex are also provided.
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Paragraph 0700
(2013/03/26)
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- Thiophosphorylation of free amino acids and enzyme protein by thiophosphoramidate ions
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In search of an activity-preserving protein thiophosphorylation method, with thymidylate synthase recombinant protein used as a substrate, potassium thiophosphoramidate and diammonium thiophosphoramidate salts in Tris- and ammonium carbonate based buffer solutions were employed, proving to serve as a non-destructive environment. Using potassium phosphoramidate or diammonium thiophosphoramidate, a series of phosphorylated and thiophosphorylated amino acid derivatives was prepared, helping, together with computational (using density functional theory, DFT) estimation of 31P NMR chemical shifts, to assign thiophosphorylated protein NMR resonances and prove the presence of thiophosphorylated lysine, serine and histidine moieties. Methods useful for prediction of 31P NMR chemical shifts of thiophosphorylated amino acid moieties, and thiophosphates in general, are also presented. The preliminary results obtained from trypsin digestion of enzyme shows peak at m/z 1825.805 which is in perfect agreement with the simulated isotopic pattern distributions for monothiophosphate of TVQQQVHLNQDEYK where thiophosphate moiety is attached to histidine (His26) or lysine (Lys33) side-chain.
- Ruman, Tomasz,Dlugopolska, Karolina,Jurkiewicz, Agata,Rut, Dagmara,Fraczyk, Tomasz,Ciesla, Joanna,Les, Andrzej,Szewczuk, Zbigniew,Rode, Wojciech
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experimental part
p. 74 - 80
(2010/05/17)
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- Optimization of the kinetic resolution of the DL-phospho-monoesters of threonine and serine by random mutagenesis of the acid phosphatase from Salmonella enterica
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Acid phosphatases are enzymes with a broad substrate specificity showing hydrolytic activity towards several different organic phosphate monoesters, such as nucleotides and sugar phosphates. The acid phosphatase from Salmonella enterica ser. typhimurium LT2 (PhoN-Se) is able to hydrolyze O-phospho-DL-threonine to yield L-threonine with a very high enantioselectivity (E > 200). When O-phospho-DL-serine was hydrolyzed by PhoN-Se, D-serine was formed, however, the ee values rapidly dropped to 50 %. Random mutagenesis by error-prone PCR was performed on the phosphatase in order to increase its enantioselectivity in the formation of D-serine. Two variants with increased selectivity from a library of 9600 mutants have been found, N151D and V78L showing E values of 18.1 and 4.1, respectively, compared to 3.4 for the wild-type (WT) enzyme.
- Van Herk, Teunie,Hartog, Aloysius F.,Ruijssenaars, Harald J.,Kerkman, Richard,Schoemaker, Hans E.,Wever, Ron
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p. 1349 - 1352
(2008/09/16)
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- Syntheses of optically pure α-amino acids from 3-amino-2-oxetanone salts
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A process for the preparation of optically pure α-amino acids comprising the nucleophilic ring-opening of 3-amino-2-oxetanone salts. N-Protected serine β-lactones are deprotected to form heretofore unknown 3-amino-2-oxetanone and its corresponding salts. In turn these previously unknown 3-amino-2-oxetanone salts may be used in the synthesis of other novel or rare stereochemically-pure free amino acids.
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