PDBsum entry 3mlc

Isomerase

PDB id: 3mlc

Contents

Protein chains

129 a.a.

Ligands

PR6 ×5

Waters ×486

PDB id:

3mlc

Name:

Isomerase

Title:

Crystal structure of fg41msad inactivated by 3-chloropropiolate

Structure:

Fg41 malonate semialdehyde decarboxylase. Chain: a, b, c, d, e. Engineered: yes

Source:

Coryneform bacterium. Organism_taxid: 1728. Strain: fg41. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

2.22Å R-factor: 0.227 R-free: 0.275

Authors:

Y.Guo,H.Serrano,G.J.Poelarends,W.H.Johnson Jr.,M.L.Hackert, C.P.Whitman

Key ref:

Y.Guo et al. (2013). Kinetic, mutational, and structural analysis of malonate semialdehyde decarboxylase from Coryneform bacterium strain FG41: mechanistic implications for the decarboxylase and hydratase activities. Biochemistry, 52, 4830-4841. PubMed id: 23781927 DOI: 10.1021/bi400567a

Date:

16-Apr-10 Release date: 06-Apr-11

Protein chains

F2Z288  (F2Z288_9CORY) -  FG41 Malonate Semialdehyde Decarboxylase from coryneform bacterium

Seq: 136 a.a.

Struc: 129 a.a.

Enzyme reactions

• Enzyme class: E.C.4.1.1.- - ?????

DOI no: 10.1021/bi400567a

Biochemistry 52:4830-4841 (2013)

PubMed id: 23781927

Kinetic, mutational, and structural analysis of malonate semialdehyde decarboxylase from Coryneform bacterium strain FG41: mechanistic implications for the decarboxylase and hydratase activities.

Y.Guo, H.Serrano, G.J.Poelarends, W.H.Johnson, M.L.Hackert, C.P.Whitman.

ABSTRACT

Malonate semialdehyde decarboxylase from Pseudomonas pavonaceae 170 (designated Pp MSAD) is in a bacterial catabolic pathway for the nematicide 1,3-dichloropropene. MSAD has two known activities: it catalyzes the metal ion-independent decarboxylation of malonate semialdehyde to produce acetaldehyde and carbon dioxide and a low-level hydration of 2-oxo-3-pentynoate to yield acetopyruvate. The latter activity is not known to be biologically relevant. Previous studies identified Pro-1, Asp-37, and a pair of arginines (Arg-73 and Arg-75) as critical residues in these activities. In terms of pairwise sequence, MSAD from Coryneform bacterium strain FG41 (designated FG41 MSAD) is 38% identical with the Pseudomonas enzyme, including Pro-1 and Asp-37. However, Gln-73 replaces Arg-73, and the second arginine is shifted to Arg-76 by the insertion of a glycine. To determine how these changes relate to the activities of FG41 MSAD, the gene was cloned and the enzyme expressed and characterized. The enzyme has a comparable decarboxylase activity but a significantly reduced hydratase activity. Mutagenesis along with crystal structures of the native enzyme (2.0 Å resolution) and the enzyme modified by a 3-oxopropanoate moiety (resulting from the incubation of the enzyme and 3-bromopropiolate) (2.2 Å resolution) provided a structural basis. The roles of Pro-1 and Asp-37 are likely the same as those proposed for Pp MSAD. However, the side chains of Thr-72, Gln-73, and Tyr-123 replace those of Arg-73 and Arg-75 in the mechanism and play a role in binding and catalysis. The structures also show that Arg-76 is likely too distant to play a direct role in the mechanism. FG41 MSAD is the second functionally annotated homologue in the MSAD family of the tautomerase superfamily and could represent a new subfamily.