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1k25

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{{STRUCTURE_1k25| PDB=1k25 | SCENE= }}
{{STRUCTURE_1k25| PDB=1k25 | SCENE= }}
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'''PBP2x from a Highly Penicillin-resistant Streptococcus pneumoniae Clinical Isolate'''
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===PBP2x from a Highly Penicillin-resistant Streptococcus pneumoniae Clinical Isolate===
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==Overview==
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Penicillin-binding proteins (PBPs) are the main targets for beta-lactam antibiotics, such as penicillins and cephalosporins, in a wide range of bacterial species. In some Gram-positive strains, the surge of resistance to treatment with beta-lactams is primarily the result of the proliferation of mosaic PBP-encoding genes, which encode novel proteins by recombination. PBP2x is a primary resistance determinant in Streptococcus pneumoniae, and its modification is an essential step in the development of high level beta-lactam resistance. To understand such a resistance mechanism at an atomic level, we have solved the x-ray crystal structure of PBP2x from a highly penicillin-resistant clinical isolate of S. pneumoniae, Sp328, which harbors 83 mutations in the soluble region. In the proximity of the Sp328 PBP2x* active site, the Thr(338) --&gt; Ala mutation weakens the local hydrogen bonding network, thus abrogating the stabilization of a crucial buried water molecule. In addition, the Ser(389) --&gt; Leu and Asn(514) --&gt; His mutations produce a destabilizing effect that generates an "open" active site. It has been suggested that peptidoglycan substrates for beta-lactam-resistant PBPs contain a large amount of abnormal, branched peptides, whereas sensitive strains tend to catalyze cross-linking of linear forms. Thus, in vivo, an "open" active site could facilitate the recognition of distinct, branched physiological substrates.
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(as it appears on PubMed at http://www.pubmed.gov), where 11553637 is the PubMed ID number.
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{{ABSTRACT_PUBMED_11553637}}
==About this Structure==
==About this Structure==
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[[Category: Clinical mutant]]
[[Category: Clinical mutant]]
[[Category: Low-affinity penicillin-binding]]
[[Category: Low-affinity penicillin-binding]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 22:12:23 2008''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 21:24:43 2008''

Revision as of 18:24, 1 July 2008

Image:1k25.png

Template:STRUCTURE 1k25

PBP2x from a Highly Penicillin-resistant Streptococcus pneumoniae Clinical Isolate

Template:ABSTRACT PUBMED 11553637

About this Structure

1K25 is a Single protein structure of sequence from Streptococcus pneumoniae. Full crystallographic information is available from OCA.

Reference

Crystal structure of PBP2x from a highly penicillin-resistant Streptococcus pneumoniae clinical isolate: a mosaic framework containing 83 mutations., Dessen A, Mouz N, Gordon E, Hopkins J, Dideberg O, J Biol Chem. 2001 Nov 30;276(48):45106-12. Epub 2001 Sep 11. PMID:11553637

Page seeded by OCA on Tue Jul 1 21:24:43 2008

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