1w28: Difference between revisions

From Proteopedia
Jump to navigationJump to search
← Older editNewer edit →
OCA (talk | contribs)
Bots, Bureaucrats, journal, Administrators
3,331,613 edits
No edit summary
OCA (talk | contribs)
Bots, Bureaucrats, journal, Administrators
3,331,613 edits
No edit summary
Line 1: Line 1:
[[Image:1w28.gif|left|200px]]
{{Seed}}
[[Image:1w28.png|left|200px]]


<!--
<!--
Line 9: Line 10:
{{STRUCTURE_1w28|  PDB=1w28  |  SCENE=  }}  
{{STRUCTURE_1w28|  PDB=1w28  |  SCENE=  }}  


'''CONFORMATIONAL FLEXIBILITY OF THE C-TERMINUS WITH IMPLICATIONS FOR SUBSTRATE BINDING AND CATALYSIS IN A NEW CRYSTAL FORM OF DEACETOXYCEPHALOSPORIN C SYNTHASE'''
===CONFORMATIONAL FLEXIBILITY OF THE C-TERMINUS WITH IMPLICATIONS FOR SUBSTRATE BINDING AND CATALYSIS IN A NEW CRYSTAL FORM OF DEACETOXYCEPHALOSPORIN C SYNTHASE===




==Overview==
<!--  
Deacetoxycephalosporin C synthase (DAOCS) from Streptomyces clavuligerus catalyses the oxidative ring expansion of the penicillin nucleus into the nucleus of cephalosporins. The reaction requires dioxygen and 2-oxoglutarate as co-substrates to create a reactive iron-oxygen intermediate from a ferrous iron in the active site. The active enzyme is monomeric in solution. The structure of DAOCS was determined earlier from merohedrally twinned crystals where the last four C-terminal residues (308-311) of one molecule penetrate the active site of a neighbouring molecule, creating a cyclic trimeric structure in the crystal. Shortening the polypeptide chain from the C terminus by more than four residues diminishes activity. Here, we describe a new crystal form of DAOCS in which trimer formation is broken and the C-terminal arm is free. These crystals show no signs of twinning, and were obtained from DAOCS labelled with an N-terminal His-tag. The modified DAOCS is catalytically active. The free C-terminal arm protrudes into the solvent, and the C-terminal domain (residues 268-299) is rotated by about 16 degrees towards the active site. The last 12 residues (300-311) are disordered. Structures for various enzyme-substrate and enzyme-product complexes in the new crystal form confirm overlapping binding sites for penicillin and 2-oxoglutarate. The results support the notion that 2-oxoglutarate and dioxygen need to react first to produce an oxidizing iron species, followed by reaction with the penicillin substrate. The position of the penicillin nucleus is topologically similar in the two crystal forms, but the penicillin side-chain in the new non-twinned crystals overlaps with the position of residues 304-306 of the C-terminal arm in the twinned crystals. An analysis of the interactions between the C-terminal region and residues in the active site indicates that DAOCS could also accept polypeptide chains as ligands, and these could bind near the iron.
The line below this paragraph, {{ABSTRACT_PUBMED_15381427}}, adds the Publication Abstract to the page
(as it appears on PubMed at http://www.pubmed.gov), where 15381427 is the PubMed ID number.
-->
{{ABSTRACT_PUBMED_15381427}}


==About this Structure==
==About this Structure==
Line 35: Line 39:
[[Category: Oxidoreductase]]
[[Category: Oxidoreductase]]
[[Category: Penicillin]]
[[Category: Penicillin]]
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May  3 13:03:03 2008''
 
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 13:28:35 2008''

Revision as of 10:28, 28 July 2008

File:1w28.png

Template:STRUCTURE 1w28

CONFORMATIONAL FLEXIBILITY OF THE C-TERMINUS WITH IMPLICATIONS FOR SUBSTRATE BINDING AND CATALYSIS IN A NEW CRYSTAL FORM OF DEACETOXYCEPHALOSPORIN C SYNTHASE

Template:ABSTRACT PUBMED 15381427

About this Structure

1W28 is a Single protein structure of sequence from Streptomyces clavuligerus. Full crystallographic information is available from OCA.

Reference

Conformational flexibility of the C terminus with implications for substrate binding and catalysis revealed in a new crystal form of deacetoxycephalosporin C synthase., Oster LM, van Scheltinga AC, Valegard K, Hose AM, Dubus A, Hajdu J, Andersson I, J Mol Biol. 2004 Oct 8;343(1):157-71. PMID:15381427

Page seeded by OCA on Mon Jul 28 13:28:35 2008

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "https://proteopedia.org/index.php?title=1w28&oldid=700624"