PDBsum entry 3ht5

Transferase

PDB id: 3ht5

Contents

Protein chain

335 a.a. *

Ligands

PMP

Waters ×281

* Residue conservation analysis

PDB id:

3ht5

Name:

Transferase

Title:

Crystal structure of ilve a branched chain amino acid transaminase from mycobacterium tuberculosis

Structure:

Branched-chain-amino-acid aminotransferase. Chain: a. Fragment: plp dependent transaminase type iv fold. Synonym: bcat. Engineered: yes. Mutation: yes

Source:

Mycobacterium tuberculosis. Organism_taxid: 1773. Gene: ilve, mt2266, mtcy190.21c, rv2210c. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

1.90Å R-factor: 0.185 R-free: 0.198

Authors:

L.W.Tremblay,J.S.Blanchard

Key ref:

L.W.Tremblay and J.S.Blanchard (2009). The 1.9 A structure of the branched-chain amino-acid transaminase (IlvE) from Mycobacterium tuberculosis. Acta Crystallogr Sect F Struct Biol Cryst Commun, 65, 1071-1077. PubMed id: 19923721

Date:

11-Jun-09 Release date: 01-Dec-09

Protein chain

P9WQ75  (ILVE_MYCTU) -  Branched-chain-amino-acid aminotransferase from Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)

Seq: 368 a.a.

Struc: 335 a.a.

Enzyme reactions

• Enzyme class: E.C.2.6.1.42 - branched-chain-amino-acid transaminase.
• Pathway: Leucine Biosynthesis
• Reaction: L-leucine + 2-oxoglutarate = 4-methyl-2-oxopentanoate + L-glutamate
• Cofactor: Pyridoxal 5'-phosphate

Pyridoxal 5'-phosphate (Bound ligand (Het Group name = PMP) matches with 88.24% similarity)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

Acta Crystallogr Sect F Struct Biol Cryst Commun 65:1071-1077 (2009)

PubMed id: 19923721

The 1.9 A structure of the branched-chain amino-acid transaminase (IlvE) from Mycobacterium tuberculosis.

L.W.Tremblay, J.S.Blanchard.

ABSTRACT

Unlike mammals, bacteria encode enzymes that synthesize branched-chain amino acids. The pyridoxal 50-phosphate-dependent transaminase performs the final biosynthetic step in these pathways, converting keto acid precursors into -amino acids. The branched-chain amino-acid transaminase from Mycobacterium tuberculosis (MtIlvE) has been crystallized and its structure has been solved at 1.9 angstrom resolution. The MtIlvE monomer is composed of two domains that interact to form the active site. The biologically active form of IlvE is a homodimer in which each monomer contributes a substrate-specificity loop to the partner molecule. Additional substrate selectivity may be imparted by a conserved N-terminal Phe30 residue, which has previously been observed to shield the active site in the type IV fold homodimer. The active site of MtIlvE contains density corresponding to bound PMP, which is likely to be a consequence of the presence of tryptone in the crystallization medium. Additionally, two cysteine residues are positioned at the dimer interface for disulfide-bond formation under oxidative conditions. It is unknown whether they are involved in any regulatory activities analogous to those of the human mitochondrial branched-chain amino-acid transaminase.