2B61

Crystal Structure of Homoserine Transacetylase

Summary for 2B61

• Entry DOI: 10.2210/pdb2b61/pdb
• Descriptor: Homoserine O-acetyltransferase (2 entities in total)
• Functional Keywords: acyl-enzyme, aspartate pathway, coenzyme a, structure-function studies, alpha-beta hydrolase fold, transferase
• Biological source: Haemophilus influenzae
• Cellular location: Cytoplasm : P45131
• Total number of polymer chains: 1
• Total formula weight: 42539.28

Authors

Mirza, I.A.,Nazi, I.,Korczynska, M.,Wright, G.D.,Berghuis, A.M. (deposition date: 2005-09-29, release date: 2005-11-15, Last modification date: 2024-11-13)

Primary citation

Mirza, I.A.,Nazi, I.,Korczynska, M.,Wright, G.D.,Berghuis, A.M.
Crystal Structure of Homoserine Transacetylase from Haemophilus influenzae Reveals a New Family of alpha/beta-Hydrolases
Biochemistry, 44:15768-15773, 2005

PubMed Abstract: Homoserine transacetylase catalyzes one of the required steps in the biosynthesis of methionine in fungi and several bacteria. We have determined the crystal structure of homoserine transacetylase from Haemophilus influenzae to a resolution of 1.65 A. The structure identifies this enzyme to be a member of the alpha/beta-hydrolase structural superfamily. The active site of the enzyme is located near the end of a deep tunnel formed by the juxtaposition of two domains and incorporates a catalytic triad involving Ser143, His337, and Asp304. A structural basis is given for the observed double displacement kinetic mechanism of homoserine transacetylase. Furthermore, the properties of the tunnel provide a rationale for how homoserine transacetylase catalyzes a transferase reaction vs hydrolysis, despite extensive similarity in active site architecture to hydrolytic enzymes.

PubMed: 16313180
DOI: 10.1021/bi051951y

Experimental method

X-RAY DIFFRACTION (1.65 Å)