1ocx
From Proteopedia
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==Overview== | ==Overview== | ||
| - | 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, ... | + | 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. |
==About this Structure== | ==About this Structure== | ||
| - | 1OCX is a | + | 1OCX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with PBM as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Maltose_O-acetyltransferase Maltose O-acetyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.1.79 2.3.1.79] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1OCX OCA]. |
==Reference== | ==Reference== | ||
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[[Category: left-handed parallel beta-helix]] | [[Category: left-handed parallel beta-helix]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 15:34:14 2007'' |
Revision as of 13:28, 5 November 2007
|
E. COLI MALTOSE-O-ACETYLTRANSFERASE
Overview
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.
About this Structure
1OCX is a Single protein structure of sequence from Escherichia coli with PBM as ligand. Active as Maltose O-acetyltransferase, with EC number 2.3.1.79 Structure known Active Site: AC1. Full crystallographic information is available from OCA.
Reference
The structure and specificity of Escherichia coli maltose acetyltransferase give new insight into the LacA family of acyltransferases., Lo Leggio L, Dal Degan F, Poulsen P, Andersen SM, Larsen S, Biochemistry. 2003 May 13;42(18):5225-35. PMID:12731863
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