1ocx: Difference between revisions
From Proteopedia
Jump to navigationJump to search
No edit summary |
No edit summary |
||
| Line 5: | Line 5: | ||
==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== | ||
| Line 23: | Line 23: | ||
[[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'' | ||
