1nx9

[[Image:1nx9.gif|left|200px]]

|PDB= 1nx9 |SIZE=350|CAPTION= <scene name='initialview01'>1nx9</scene>, resolution 2.20&Aring;

|SITE=

|LIGAND= <scene name='pdbligand=AIC:(2S,5R,6R)-6-{[(2R)-2-AMINO-2-PHENYLETHANOYL]AMINO}-3,3-DIMETHYL-7-OXO-4-THIA-1-AZABICYCLO[3.2.0]HEPTANE-2-CARBOXYLIC+ACID'>AIC</scene> and <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>

|ACTIVITY= [http://en.wikipedia.org/wiki/Alpha-amino-acid_esterase Alpha-amino-acid esterase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.1.43 3.1.1.43]

 

 

 

==Overview==

The alpha-amino acid ester hydrolase (AEH) from Acetobacter turbidans is a bacterial enzyme catalyzing the hydrolysis and synthesis of beta-lactam antibiotics. The crystal structures of the native enzyme, both unliganded and in complex with the hydrolysis product D-phenylglycine are reported, as well as the structures of an inactive mutant (S205A) complexed with the substrate ampicillin, and an active site mutant (Y206A) with an increased tendency to catalyze antibiotic production rather than hydrolysis. The structure of the native enzyme shows an acyl binding pocket, in which D-phenylglycine binds, and an additional space that is large enough to accommodate the beta-lactam moiety of an antibiotic. In the S205A mutant, ampicillin binds in this pocket in a non-productive manner, making extensive contacts with the side chain of Tyr(112), which also participates in oxyanion hole formation. In the Y206A mutant, the Tyr(112) side chain has moved with its hydroxyl group toward the catalytic serine. Because this changes the properties of the beta-lactam binding site, this could explain the increased beta-lactam transferase activity of this mutant.

 

==About this Structure==

1NX9 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Acetobacter_pasteurianus Acetobacter pasteurianus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NX9 OCA].

 

==Reference==

Acetobacter turbidans alpha-amino acid ester hydrolase: how a single mutation improves an antibiotic-producing enzyme., Barends TR, Polderman-Tijmes JJ, Jekel PA, Williams C, Wybenga G, Janssen DB, Dijkstra BW, J Biol Chem. 2006 Mar 3;281(9):5804-10. Epub 2005 Dec 23. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/16377627 16377627]

[[Category: Alpha-amino-acid esterase]]

[[Category: Single protein]]

[[Category: Barends, T R.M.]]

[[Category: Dijkstra, B W.]]

[[Category: Janssen, D B.]]

[[Category: Jekel, P A.]]

[[Category: Polderman-Tijmes, J J.]]