1OCX

E. coli maltose-O-acetyltransferase

Summary for 1OCX

• Entry DOI: 10.2210/pdb1ocx/pdb
• Descriptor: MALTOSE O-ACETYLTRANSFERASE, TRIMETHYL LEAD ION (3 entities in total)
• Functional Keywords: transferase, acetyl transferase, left-handed parallel beta-helix
• Biological source: ESCHERICHIA COLI
• Total number of polymer chains: 3
• Total formula weight: 61224.83

Authors

Lo Leggio, L.,Dal Degan, F.,Poulsen, P.,Larsen, S. (deposition date: 2003-02-11, release date: 2003-06-12, Last modification date: 2024-05-08)

Primary citation

Lo Leggio, L.,Degan, F.D.,Poulsen, P.,Andersen, S.M.,Larsen, S.
The Structure and Specificity of Escherichia Coli Maltose Acetyltransferase Give New Insight Into the Laca Family of Acyltransferases.
Biochemistry, 42:5225-, 2003

PubMed Abstract: The crystallographic three-dimensional structure of the Escherichia coli maa gene product, previously identified as a maltose O-acetyltransferase (MAT) [Brand, B., and Boos, W. (1991) J. Biol. Chem. 266, 14113-14118] has been determined to 2.15 A resolution by the single anomalous dispersion method using data from a crystal cocrystallized with trimethyllead acetate. It is shown here that MAT acetylates glucose exclusively at the C6 position and maltose at the C6 position of the nonreducing end glucosyl moiety. Furthermore, MAT shows higher affinity toward artificial substrates containing an alkyl or hydrophobic chain as well as a glucosyl unit. The presence of a long hydrophobic patch near the acceptor site provides the structural explanation for this preference. The three-dimensional structure reveals the expected trimeric left-handed parallel beta-helix structure found in all other known hexapeptide repeat enzymes. In particular, the structure shows similarities both overall and at the putative active site to the recently determined structure of galactoside acetyltransferase (GAT), the lacA gene product [Wang, X.-G., Olsen, L. R., and Roderick, S. L. (2002) Structure 10, 581-588]. The structure, together with the new biochemical data, suggests that GAT and MAT are more closely related than previously thought and might have similar cellular functions. However, while GAT is specific for acetylation of galactosyl units, MAT is specific for glucosyl units and is able to acetylate maltooligosaccharides, an important property for biotechnological applications. Structural differences at the acceptor site reflect the differences in substrate specificity.

PubMed: 12731863
DOI: 10.1021/BI0271446

Experimental method

X-RAY DIFFRACTION (2.15 Å)