Enzymes
UniProtKB help_outline | 6,989 proteins |
Enzyme class help_outline |
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- Name help_outline D-maltose Identifier CHEBI:17306 (CAS: 69-79-4) help_outline Charge 0 Formula C12H22O11 InChIKeyhelp_outline GUBGYTABKSRVRQ-PICCSMPSSA-N SMILEShelp_outline OC[C@H]1O[C@H](O[C@@H]2[C@@H](CO)OC(O)[C@H](O)[C@H]2O)[C@H](O)[C@@H](O)[C@@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 18 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline ATP Identifier CHEBI:30616 (Beilstein: 3581767) help_outline Charge -4 Formula C10H12N5O13P3 InChIKeyhelp_outline ZKHQWZAMYRWXGA-KQYNXXCUSA-J SMILEShelp_outline Nc1ncnc2n(cnc12)[C@@H]1O[C@H](COP([O-])(=O)OP([O-])(=O)OP([O-])([O-])=O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 1,284 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline α-maltose 1-phosphate Identifier CHEBI:63576 Charge -2 Formula C12H21O14P InChIKeyhelp_outline VRKQBSISJQUWFI-QUYVBRFLSA-L SMILEShelp_outline OC[C@H]1O[C@H](O[C@H]2[C@H](O)[C@@H](O)[C@H](O[C@@H]2CO)OP([O-])([O-])=O)[C@H](O)[C@@H](O)[C@@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 3 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline ADP Identifier CHEBI:456216 (Beilstein: 3783669) help_outline Charge -3 Formula C10H12N5O10P2 InChIKeyhelp_outline XTWYTFMLZFPYCI-KQYNXXCUSA-K SMILEShelp_outline Nc1ncnc2n(cnc12)[C@@H]1O[C@H](COP([O-])(=O)OP([O-])([O-])=O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 841 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,521 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:31915 | RHEA:31916 | RHEA:31917 | RHEA:31918 | |
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Publications
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Homotypic dimerization of a maltose kinase for molecular scaffolding.
Li J., Guan X., Shaw N., Chen W., Dong Y., Xu X., Li X., Rao Z.
Mycobacterium tuberculosis (Mtb) uses maltose-1-phosphate to synthesize α-glucans that make up the major component of its outer capsular layer. Maltose kinase (MaK) catalyzes phosphorylation of maltose. The molecular basis for this phosphorylation is currently not understood. Here, we describe the ... >> More
Mycobacterium tuberculosis (Mtb) uses maltose-1-phosphate to synthesize α-glucans that make up the major component of its outer capsular layer. Maltose kinase (MaK) catalyzes phosphorylation of maltose. The molecular basis for this phosphorylation is currently not understood. Here, we describe the first crystal structure of MtbMaK refined to 2.4 Å resolution. The bi-modular architecture of MtbMaK reveals a remarkably unique N-lobe. An extended sheet protrudes into ligand binding pocket of an adjacent monomer and contributes residues critical for kinase activity. Structure of the complex of MtbMaK bound with maltose reveals that maltose binds in a shallow cavity of the C-lobe. Structural constraints permit phosphorylation of α-maltose only. Surprisingly, instead of a Gly-rich loop, MtbMaK employs 'EQS' loop to tether ATP. Notably, this loop is conserved across all MaK homologues. Structures of MtbMaK presented here unveil features that are markedly different from other kinases and support the scaffolding role proposed for this kinase. << Less
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Structure of mycobacterial maltokinase, the missing link in the essential GlgE-pathway.
Fraga J., Maranha A., Mendes V., Pereira P.J., Empadinhas N., Macedo-Ribeiro S.
A novel four-step pathway identified recently in mycobacteria channels trehalose to glycogen synthesis and is also likely involved in the biosynthesis of two other crucial polymers: intracellular methylglucose lipopolysaccharides and exposed capsular glucan. The structures of three of the interven ... >> More
A novel four-step pathway identified recently in mycobacteria channels trehalose to glycogen synthesis and is also likely involved in the biosynthesis of two other crucial polymers: intracellular methylglucose lipopolysaccharides and exposed capsular glucan. The structures of three of the intervening enzymes - GlgB, GlgE, and TreS - were recently reported, providing the first templates for rational drug design. Here we describe the structural characterization of the fourth enzyme of the pathway, mycobacterial maltokinase (Mak), uncovering a eukaryotic-like kinase (ELK) fold, similar to methylthioribose kinases and aminoglycoside phosphotransferases. The 1.15 Å structure of Mak in complex with a non-hydrolysable ATP analog reveals subtle structural rearrangements upon nucleotide binding in the cleft between the N- and the C-terminal lobes. Remarkably, this new family of ELKs has a novel N-terminal domain topologically resembling the cystatin family of protease inhibitors. By interfacing with and restraining the mobility of the phosphate-binding region of the N-terminal lobe, Mak's unusual N-terminal domain might regulate its phosphotransfer activity and represents the most likely anchoring point for TreS, the upstream enzyme in the pathway. By completing the gallery of atomic-detail models of an essential pathway, this structure opens new avenues for the rational design of alternative anti-tubercular compounds. << Less
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Biochemical characterization of the maltokinase from Mycobacterium bovis BCG.
Mendes V., Maranha A., Lamosa P., da Costa M.S., Empadinhas N.
<h4>Background</h4>Maltose-1-phosphate was detected in Mycobacterium bovis BCG extracts in the 1960's but a maltose-1-phosphate synthetase (maltokinase, Mak) was only much later purified from Actinoplanes missouriensis, allowing the identification of the mak gene. Recently, this metabolite was pro ... >> More
<h4>Background</h4>Maltose-1-phosphate was detected in Mycobacterium bovis BCG extracts in the 1960's but a maltose-1-phosphate synthetase (maltokinase, Mak) was only much later purified from Actinoplanes missouriensis, allowing the identification of the mak gene. Recently, this metabolite was proposed to be the intermediate in a pathway linking trehalose with the synthesis of glycogen in M. smegmatis. Although the M. tuberculosis H37Rv mak gene (Rv0127) was considered essential for growth, no mycobacterial Mak has, to date, been characterized.<h4>Results</h4>The sequence of the Mak from M. bovis BCG was identical to that from M. tuberculosis strains (99-100% amino acid identity). The enzyme was dependent on maltose and ATP, although GTP and UTP could be used to produce maltose-1-phosphate, which we identified by TLC and characterized by NMR. The Km for maltose was 2.52 +/- 0.40 mM and 0.74 +/-0.12 mM for ATP; the Vmax was 21.05 +/-0.89 micromol/min x mg(-1). Divalent cations were required for activity and Mg2+ was the best activator. The enzyme was a monomer in solution, had maximal activity at 60 degrees C, between pH 7 and 9 (at 37 degrees C) and was unstable on ice and upon freeze/thawing. The addition of 50 mM NaCl markedly enhanced Mak stability.<h4>Conclusions</h4>The unknown role of maltokinases in mycobacterial metabolism and the lack of biochemical data led us to express the mak gene from M. bovis BCG for biochemical characterization. This is the first mycobacterial Mak to be characterized and its properties represent essential knowledge towards deeper understanding of mycobacterial physiology. Since Mak may be a potential drug target in M. tuberculosis, its high-level production and purification in bioactive form provide important tools for further functional and structural studies. << Less
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Maltokinase (ATP:maltose 1-phosphotransferase) from Actinoplanes sp.: demonstration of enzyme activity and characterization of the reaction product.
Drepper A., Peitzmann R., Pape H.
Cell free extract of the acarbose producer Actinoplanes sp. catalyzes ATP-dependent phosphorylation of maltose. This was shown by two different assays. The product was purified and its structure determined to be alpha-maltose-1-phosphate by chemical analysis and NMR spectroscopy.