PDBsum entry: 1saz

Transferase

PDB id: 1saz

Contents

Protein chain

375 a.a. *

Ligands

ACP

FMT ×4

Metals

_NA

Waters ×63

* Residue conservation analysis

PDB id:

1saz

Name:

Transferase

Title:

Membership in the askha superfamily: enzymological properties and crystal structure of butyrate kinase 2 from thermotoga maritima

Structure:

Probable butyrate kinase 2. Chain: a. Synonym: bk 2, branched-chain carboxylic acid kinase 2. Engineered: yes

Source:

Thermotoga maritima. Organism_taxid: 2336. Gene: buk2, tm1756. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Dimer (from PDB file)

Resolution:

2.50Å R-factor: 0.217 R-free: 0.267

Authors:

J.Diao,D.R.Cooper,D.A.Sanders,M.S.Hasson

Key ref:

J.Diao and M.S.Hasson (2009). Crystal structure of butyrate kinase 2 from Thermotoga maritima, a member of the ASKHA superfamily of phosphotransferases. J Bacteriol, 191, 2521-2529. PubMed id: 19201797 DOI: 10.1128/JB.00906-08

Date:

09-Feb-04 Release date: 29-Mar-05

Protein chain

Q9X278  (BUK2_THEMA) -  Probable butyrate kinase 2

Seq: 375 a.a.

Struc: 375 a.a.

Enzyme reactions

• Enzyme class: E.C.2.7.2.7 - Butyrate kinase.
• Reaction: ATP + butanoate = ADP + butanoyl phosphate

ATP + butanoate (Bound ligand (Het Group name = FMT) matches with 50.00% similarity) = ADP (Bound ligand (Het Group name = ACP) matches with 81.00% similarity) + butanoyl phosphate

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

 Gene Ontology (GO) functional annotation 

• Cellular component: intracellular (2 terms)
• Biological process: metabolic process (2 terms)
• Biochemical function: nucleotide binding (6 terms)

reference

DOI no: 10.1128/JB.00906-08

J Bacteriol 191:2521-2529 (2009)

PubMed id: 19201797

Crystal structure of butyrate kinase 2 from Thermotoga maritima, a member of the ASKHA superfamily of phosphotransferases.

J.Diao, M.S.Hasson.

ABSTRACT

The enzymatic transfer of phosphoryl groups is central to the control of many cellular processes. One of the phosphoryl transfer mechanisms, that of acetate kinase, is not completely understood. Besides better understanding of the mechanism of acetate kinase, knowledge of the structure of butyrate kinase 2 (Buk2) will aid in the interpretation of active-site structure and provide information on the structural basis of substrate specificity. The gene buk2 from Thermotoga maritima encodes a member of the ASKHA (acetate and sugar kinases/heat shock cognate/actin) superfamily of phosphotransferases. The encoded protein Buk2 catalyzes the phosphorylation of butyrate and isobutyrate. We have determined the 2.5-A crystal structure of Buk2 complexed with (beta,gamma-methylene) adenosine 5'-triphosphate. Buk2 folds like an open-shelled clam, with each of the two domains representing one of the two shells. In the open active-site cleft between the N- and C-terminal domains, the active-site residues consist of two histidines, two arginines, and a cluster of hydrophobic residues. The ATP binding region of Buk2 in the C-terminal domain consists of abundant glycines for nucleotide binding, and the ATP binding motif is similar to those of other members of the ASKHA superfamily. The enzyme exists as an octamer, in which four disulfide bonds form between intermolecular cysteines. Sequence alignment and structure superposition identify the simplicity of the monomeric Buk2 structure, a probable substrate binding site, the key residues in catalyzing phosphoryl transfer, and the substrate specificity differences among Buk2, acetate, and propionate kinases. The possible enzyme mechanisms are discussed.