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357 a.a.
Bound ligand (Het Group name = AS2) corresponds exactly |
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 phosphate |
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 NADP(+) |
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 L-4-aspartyl phosphate |
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 NADPH |
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Key reference
DOI no: 10.1107/S0907444904012971 Acta Crystallogr D Biol Crystallogr 60:1388-1395 (2004) PubMed id: 15272161
The role of substrate-binding groups in the mechanism of aspartate-beta-semialdehyde dehydrogenase. J.Blanco, R.A.Moore, C.R.Faehnle, D.M.Coe, R.E.Viola. ABSTRACT
The reversible dephosphorylation of beta-aspartyl phosphate to L-aspartate-beta-semialdehyde (ASA) in the aspartate biosynthetic pathway is catalyzed by aspartate-beta-semialdehyde dehydrogenase (ASADH). The product of this reaction is a key intermediate in the biosynthesis of diaminopimelic acid, an integral component of bacterial cell walls and a metabolic precursor of lysine and also a precursor in the biosynthesis of threonine, isoleucine and methionine. The structures of selected Haemophilus influenzae ASADH mutants were determined in order to evaluate the residues that are proposed to interact with the substrates ASA or phosphate. The substrate Km values are not altered by replacement of either an active-site arginine (Arg270) with a lysine or a putative phosphate-binding group (Lys246) with an arginine. However, the interaction of phosphate with the enzyme is adversely affected by replacement of Arg103 with lysine and is significantly altered when a neutral leucine is substituted at this position. A conservative Glu243 to aspartate mutant does not alter either ASA or phosphate binding, but instead results in an eightfold increase in the Km for the coenzyme NADP. Each of the mutations is shown to cause specific subtle active-site structural alterations and each of these changes results in decreases in catalytic efficiency ranging from significant (approximately 3% native activity) to substantial (<0.1% native activity).
Selected figure(s)
Figure 1.
Figure 1 An abbreviated mechanism of the reaction catalyzed by aspartate-semialdehyde dehydrogenase.
Figure 4.
Figure 4 Overlay of the backbone drawings of native (light) and R103L mutant (dark) hiASADH structures. (a) The overall fold and backbone position of the native and mutant structures are essentially the same, except for the reorientation of a critical active-site loop (shown in red). (b) Disruption of the water-mediated hydrogen-bonding network between Arg103 and Asn135 in the R103L mutant that triggers this loop movement and shifts the position of the active-site Cys136 nucleophile. The calculation for the overlay was performed with XtalView and the drawing was produced using SPOCK.The above figures are reprinted by permission from the IUCr: Acta Crystallogr D Biol Crystallogr (2004, 60, 1388-1395) copyright 2004. Figures were selected by an automated process.
Literature references that cite this PDB file's key reference
PubMed id Reference
18236087 A.Singh, H.R.Kushwaha, and P.Sharma (2008).
Molecular modelling and comparative structural account of aspartyl beta-semialdehyde dehydrogenase of Mycobacterium tuberculosis (H37Rv).J Mol Model, 14, 249-263.
16240442 T.Nonaka, A.Kita, J.Miura-Ohnuma, E.Katoh, N.Inagaki, T.Yamazaki, and K.Miki (2005).
Crystal structure of putative N-acetyl-gamma-glutamyl-phosphate reductase (AK071544) from rice (Oryza sativa).Proteins, 61, 1137-1140.
PDB code: 2cvo The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time. Where a reference describes a PDB structure, the PDB code is shown on the right.
Added reference
DOI no: 10.1107/S0907444904020104 Acta Crystallogr D Biol Crystallogr 60:1808-1815 (2004) PubMed id: 15388927
Critical catalytic functional groups in the mechanism of aspartate-beta-semialdehyde dehydrogenase. J.Blanco, R.A.Moore, C.R.Faehnle, R.E.Viola. ABSTRACT
The reversible dephosphorylation of beta-aspartyl phosphate to L-aspartate-beta-semialdehyde (ASA) in the aspartate biosynthetic pathway is catalyzed by aspartate-beta-semialdehyde dehydrogenase (ASADH). The product of this reaction is a key intermediate in the biosynthesis of diaminopimelic acid, an integral component of bacterial cell walls and a metabolic precursor of lysine and also a precursor in the biosynthesis of threonine, isoleucine and methionine. The structures of selected Haemophilus influenzae ASADH mutants were determined in order to evaluate the residues that are proposed to interact with the substrates ASA or phosphate. The substrate Km values are not altered by replacement of either an active-site arginine (Arg270) with a lysine or a putative phosphate-binding group (Lys246) with an arginine. However, the interaction of phosphate with the enzyme is adversely affected by replacement of Arg103 with lysine and is significantly altered when a neutral leucine is substituted at this position. A conservative Glu243 to aspartate mutant does not alter either ASA or phosphate binding, but instead results in an eightfold increase in the Km for the coenzyme NADP. Each of the mutations is shown to cause specific subtle active-site structural alterations and each of these changes results in decreases in catalytic efficiency ranging from significant (approximately 3% native activity) to substantial (<0.1% native activity).
Selected figure(s)
Figure 1.
Figure 1 The reductive dephosphorylation of [43][beta] -aspartyl phosphate to L-aspartate- [44][beta] -semialdehyde. This reaction proceeds through a covalent acyl-enzyme intermediate catalyzed by ASADH.Figure 3.
Figure 3 Representation of the 2F[o] - F[c] electron-density map of the active site of the hiASADH C136S mutant with bound ASA and phosphate. The hydroxyl group of Ser136 is pointing away from the catalytic His277 that is proposed to deprotonate the active-site nucleophile. This figure, contoured at 1.3 [128][sigma] , was produced using BOBSCRIPT and RASTER3D.The above figures are reprinted by permission from the IUCr: Acta Crystallogr D Biol Crystallogr (2004, 60, 1808-1815) copyright 2004. Figures were selected by an automated process.
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