1k5s: Difference between revisions

Revision as of 22:20, 2 May 2008

PENICILLIN ACYLASE, MUTANT COMPLEXED WITH PPA

OverviewOverview

Penicillin acylase catalyses the condensation of Calpha-substituted phenylacetic acids with beta-lactam nucleophiles, producing semi-synthetic beta-lactam antibiotics. For efficient synthesis a low affinity for phenylacetic acid and a high affinity for Calpha-substituted phenylacetic acid derivatives is desirable. We made three active site mutants, alphaF146Y, betaF24A and alphaF146Y/betaF24A, which all had a 2- to 10-fold higher affinity for Calpha-substituted compounds than wild-type enzyme. In addition, betaF24A had a 20-fold reduced affinity for phenylacetic acid. The molecular basis of the improved properties was investigated by X-ray crystallography. These studies showed that the higher affinity of alphaF146Y for (R)-alpha-methylphenylacetic acid can be explained by van der Waals interactions between alphaY146:OH and the Calpha-substituent. The betaF24A mutation causes an opening of the phenylacetic acid binding site. Only (R)-alpha-methylphenylacetic acid, but not phenylacetic acid, induces a conformation with the ligand tightly bound, explaining the weak binding of phenylacetic acid. A comparison of the betaF24A structure with other open conformations of penicillin acylase showed that betaF24 has a fixed position, whereas alphaF146 acts as a flexible lid on the binding site and reorients its position to achieve optimal substrate binding.

About this StructureAbout this Structure

1K5S is a Protein complex structure of sequences from Escherichia coli. Full crystallographic information is available from OCA.

ReferenceReference

Structural and kinetic studies on ligand binding in wild-type and active-site mutants of penicillin acylase., Alkema WB, Hensgens CM, Snijder HJ, Keizer E, Dijkstra BW, Janssen DB, Protein Eng Des Sel. 2004 May;17(5):473-80. Epub 2004 Jul 14. PMID:15254299 Page seeded by OCA on Fri May 2 22:20:50 2008

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

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 [[Image:1k5s.jpg|left|200px]]
- {{Structure
+<!--
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+The line below this paragraph, containing "STRUCTURE_1k5s", creates the "Structure Box" on the page.
-|SITE=
+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=GRO:R-2-PHENYL-PROPRIONIC+ACID'>GRO</scene>
+or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Penicillin_amidase Penicillin amidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.1.11 3.5.1.11] </span>
+or leave the SCENE parameter empty for the default display.
-|GENE= PAC ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 Escherichia coli])
+-->
-|DOMAIN=
+{{STRUCTURE_1k5s|  PDB=1k5s  |  SCENE=  }}
-|RELATEDENTRY=[[1jx9|1JX9]], [[1fxv|1FXV]], [[1pnk|1PNK]], [[1pnl|1PNL]]
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1k5s FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1k5s OCA], [http://www.ebi.ac.uk/pdbsum/1k5s PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1k5s RCSB]</span>
-}}
 '''PENICILLIN ACYLASE, MUTANT COMPLEXED WITH PPA'''
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 [[Category: Keizer, E.]]
 [[Category: Snijder, H J.]]
-[[Category: beta-strand]]
+[[Category: Beta-strand]]
-[[Category: helice]]
+[[Category: Helice]]
-[[Category: ntn-hydrolase fold]]
+[[Category: Ntn-hydrolase fold]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 22:20:50 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 21:43:51 2008''