PDBsum entry 4m6h

Hydrolase

PDB id: 4m6h

Contents

Protein chains

190 a.a.

162 a.a.

Waters ×79

PDB id:

4m6h

Name:

Hydrolase

Title:

Structure of the reduced, metal-free form of mycobacterium tuberculosis peptidoglycan amidase rv3717

Structure:

Peptidoglycan amidase rv3717. Chain: a, b. Fragment: unp residues 20-241. Synonym: n-acetymuramyl-l-alanine amidase-related protein. Engineered: yes

Source:

Mycobacterium tuberculosis. Organism_taxid: 83332. Strain: h37rv. Gene: mt3820, rv3717. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.19Å R-factor: 0.208 R-free: 0.233

Authors:

D.M.Prigozhin,D.Mavrici,J.P.Huizar,H.J.Vansell,T.Alber,Tb Structural Genomics Consortium (Tbsgc)

Key ref:

D.M.Prigozhin et al. (2013). Structural and biochemical analyses of Mycobacterium tuberculosis N-acetylmuramyl-L-alanine amidase Rv3717 point to a role in peptidoglycan fragment recycling. J Biol Chem, 288, 31549-31555. PubMed id: 24019530 DOI: 10.1074/jbc.M113.510792

Date:

09-Aug-13 Release date: 18-Sep-13

Protein chain

O69684  (O69684_MYCTO) -  N-acetymuramyl-L-alanine amidase-related protein from Mycobacterium tuberculosis (strain CDC 1551 / Oshkosh)

Seq: 241 a.a.

Struc: 190 a.a.

Protein chain

O69684  (O69684_MYCTO) -  N-acetymuramyl-L-alanine amidase-related protein from Mycobacterium tuberculosis (strain CDC 1551 / Oshkosh)

Seq: 241 a.a.

Struc: 162 a.a.*

* PDB and UniProt seqs differ at 12 residue positions (black crosses)

Enzyme reactions

• Enzyme class: Chains A, B: E.C.3.5.-.-

DOI no: 10.1074/jbc.M113.510792

J Biol Chem 288:31549-31555 (2013)

PubMed id: 24019530

Structural and biochemical analyses of Mycobacterium tuberculosis N-acetylmuramyl-L-alanine amidase Rv3717 point to a role in peptidoglycan fragment recycling.

D.M.Prigozhin, D.Mavrici, J.P.Huizar, H.J.Vansell, T.Alber.

ABSTRACT

Peptidoglycan hydrolases are key enzymes in bacterial cell wall homeostasis. Understanding the substrate specificity and biochemical activity of peptidoglycan hydrolases in Mycobacterium tuberculosis is of special interest as it can aid in the development of new cell wall targeting therapeutics. In this study, we report biochemical and structural characterization of the mycobacterial N-acetylmuramyl-l-alanine amidase, Rv3717. The crystal structure of Rv3717 in complex with a dipeptide product shows that, compared with previously characterized peptidoglycan amidases, the enzyme contains an extra disulfide-bonded β-hairpin adjacent to the active site. The structure of two intermediates in assembly reveal that Zn(2+) binding rearranges active site residues, and disulfide formation promotes folding of the β-hairpin. Although Zn(2+) is required for hydrolysis of muramyl dipeptide, disulfide oxidation is not required for activity on this substrate. The orientation of the product in the active site suggests a role for a conserved glutamate (Glu-200) in catalysis; mutation of this residue abolishes activity. The product binds at the head of a closed tunnel, and the enzyme showed no activity on polymerized peptidoglycan. These results point to a potential role for Rv3717 in peptidoglycan fragment recycling.