1dy6
From Proteopedia
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==Overview== | ==Overview== | ||
| - | The structure of the beta-lactamase SME-1 from Serratia marcescens, a | + | The structure of the beta-lactamase SME-1 from Serratia marcescens, a class A enzyme characterized by its significant activity against imipenem, has been determined to 2.13 A resolution. The overall structure of SME-1 is similar to that of other class A beta-lactamases. In the active-site cavity, most of the residues found in SME-1 are conserved among class A beta-lactamases, except at positions 104, 105 and 237, where a tyrosine, a histidine and a serine are found, respectively, and at position 238, which is occupied by a cysteine forming a disulfide bridge with the other cysteine residue located at position 69. The crucial role played by this disulfide bridge in SME-1 was confirmed by site-directed mutagenesis of Cys69 to Ala, which resulted in a mutant unable to confer resistance to imipenem and all other beta-lactam antibiotics tested. Another striking structural feature found in SME-1 was the short distance separating the side chains of the active serine residue at position 70 and the strictly conserved glutamate at position 166, which is up to 1.4 A shorter in SME-1 compared with other class A beta-lactamases. Consequently, the SME-1 structure cannot accommodate the essential catalytic water molecule found between Ser70 and Glu166 in the other class A beta-lactamases described so far, suggesting that a significant conformational change may be necessary in SME-1 to properly position the hydrolytic water molecule involved in the hydrolysis of the acyl-enzyme intermediate. |
==About this Structure== | ==About this Structure== | ||
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[[Category: Delettre, J.]] | [[Category: Delettre, J.]] | ||
[[Category: Guillet, V.]] | [[Category: Guillet, V.]] | ||
| - | [[Category: Hermite, G | + | [[Category: Hermite, G L.]] |
[[Category: Jarlier, V.]] | [[Category: Jarlier, V.]] | ||
[[Category: Naas, T.]] | [[Category: Naas, T.]] | ||
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[[Category: lactamase]] | [[Category: lactamase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:21:48 2008'' |
Revision as of 10:21, 21 February 2008
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STRUCTURE OF THE IMIPENEM-HYDROLYZING BETA-LACTAMASE SME-1
Overview
The structure of the beta-lactamase SME-1 from Serratia marcescens, a class A enzyme characterized by its significant activity against imipenem, has been determined to 2.13 A resolution. The overall structure of SME-1 is similar to that of other class A beta-lactamases. In the active-site cavity, most of the residues found in SME-1 are conserved among class A beta-lactamases, except at positions 104, 105 and 237, where a tyrosine, a histidine and a serine are found, respectively, and at position 238, which is occupied by a cysteine forming a disulfide bridge with the other cysteine residue located at position 69. The crucial role played by this disulfide bridge in SME-1 was confirmed by site-directed mutagenesis of Cys69 to Ala, which resulted in a mutant unable to confer resistance to imipenem and all other beta-lactam antibiotics tested. Another striking structural feature found in SME-1 was the short distance separating the side chains of the active serine residue at position 70 and the strictly conserved glutamate at position 166, which is up to 1.4 A shorter in SME-1 compared with other class A beta-lactamases. Consequently, the SME-1 structure cannot accommodate the essential catalytic water molecule found between Ser70 and Glu166 in the other class A beta-lactamases described so far, suggesting that a significant conformational change may be necessary in SME-1 to properly position the hydrolytic water molecule involved in the hydrolysis of the acyl-enzyme intermediate.
About this Structure
1DY6 is a Single protein structure of sequence from Serratia marcescens. Active as Beta-lactamase, with EC number 3.5.2.6 Known structural/functional Sites: and . Full crystallographic information is available from OCA.
Reference
Structure of the imipenem-hydrolyzing class A beta-lactamase SME-1 from Serratia marcescens., Sougakoff W, L'Hermite G, Pernot L, Naas T, Guillet V, Nordmann P, Jarlier V, Delettre J, Acta Crystallogr D Biol Crystallogr. 2002 Feb;58(Pt 2):267-74. Epub 2002, Jan 24. PMID:11807251
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