PDBsum entry: 1lba

Hydrolase(acting on linear amides)

PDB id: 1lba

Contents

Protein chain

146 a.a. *

Metals

_ZN

Waters ×26

* Residue conservation analysis

PDB id:

1lba

Name:

Hydrolase(acting on linear amides)

Title:

The structure of bacteriophage t7 lysozyme, a zinc amidase and an inhibitor of t7 RNA polymerase

Structure:

T7 lysozyme. Chain: a. Engineered: yes

Source:

Enterobacteria phage t7. Organism_taxid: 10760. Gene: t7.

Resolution:

2.20Å R-factor: 0.190

Authors:

X.Cheng

Key ref:

X.Cheng et al. (1994). The structure of bacteriophage T7 lysozyme, a zinc amidase and an inhibitor of T7 RNA polymerase. Proc Natl Acad Sci U S A, 91, 4034-4038. PubMed id: 8171031 DOI: 10.1073/pnas.91.9.4034

Date:

22-Dec-93 Release date: 30-Apr-94

Protein chain

P00806  (NAAA_BPT7) -  N-acetylmuramoyl-L-alanine amidase

Seq: 151 a.a.

Struc: 146 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.3.5.1.28 - N-acetylmuramoyl-L-alanine amidase.
• Reaction: Hydrolyzes the link between N-acetylmuramoyl residues and L-amino acid residues in certain bacterial cell-wall glycopeptides.

 Gene Ontology (GO) functional annotation 

• Biological process: peptidoglycan catabolic process (1 term)
• Biochemical function: protein binding (4 terms)

DOI no: 10.1073/pnas.91.9.4034

Proc Natl Acad Sci U S A 91:4034-4038 (1994)

PubMed id: 8171031

The structure of bacteriophage T7 lysozyme, a zinc amidase and an inhibitor of T7 RNA polymerase.

X.Cheng, X.Zhang, J.W.Pflugrath, F.W.Studier.

ABSTRACT

The lysozyme of bacteriophage T7 is a bifunctional protein that cuts amide bonds in the bacterial cell wall and binds to and inhibits transcription by T7 RNA polymerase. The structure of a mutant T7 lysozyme has been determined by x-ray crystallography and refined at 2.2-A resolution. The protein folds into an alpha/beta-sheet structure that has a prominent cleft. A zinc atom is located in the cleft, bound directly to three amino acids and, through a water molecule, to a fourth. Zinc is required for amidase activity but not for inhibition of T7 RNA polymerase. Alignment of the zinc ligands of T7 lysozyme with those of carboxypeptidase A and thermolysin suggests structural similarity among the catalytic sites for the amidase and these zinc proteases. Mutational analysis identified presumed catalytic residues for amidase activity within the cleft and a surface that appears to be the site of binding to T7 RNA polymerase. Binding of T7 RNA polymerase inhibits amidase activity.