2g2w: Difference between revisions

[[Image:2g2w.gif|left|200px]]<br /><applet load="2g2w" size="350" color="white" frame="true" align="right" spinBox="true"  

Beta-lactamase inhibitor protein (BLIP) binds a variety of class A beta-lactamases with affinities ranging from micromolar to picomolar. Whereas the TEM-1 and SHV-1 beta-lactamases are almost structurally identical, BLIP binds TEM-1 approximately 1000-fold tighter than SHV-1. Determining the underlying source of this affinity difference is important for understanding the molecular basis of beta-lactamase inhibition and mechanisms of protein-protein interface specificity and affinity. Here we present the 1.6A resolution crystal structure of SHV-1.BLIP. In addition, a point mutation was identified, SHV D104E, that increases SHV.BLIP binding affinity from micromolar to nanomolar. Comparison of the SHV-1.BLIP structure with the published TEM-1.BLIP structure suggests that the increased volume of Glu-104 stabilizes a key binding loop in the interface. Solution of the 1.8A SHV D104K.BLIP crystal structure identifies a novel conformation in which this binding loop is removed from the interface. Using these structural data, we evaluated the ability of EGAD, a program developed for computational protein design, to calculate changes in the stability of mutant beta-lactamase.BLIP complexes. Changes in binding affinity were calculated within an error of 1.6 kcal/mol of the experimental values for 112 mutations at the TEM-1.BLIP interface and within an error of 2.2 kcal/mol for 24 mutations at the SHV-1.BLIP interface. The reasonable success of EGAD in predicting changes in interface stability is a promising step toward understanding the stability of the beta-lactamase.BLIP complexes and computationally assisted design of tight binding BLIP variants.

2G2W is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Klebsiella_pneumoniae Klebsiella pneumoniae] and [http://en.wikipedia.org/wiki/Streptomyces_clavuligerus Streptomyces clavuligerus]. Active as [http://en.wikipedia.org/wiki/Beta-lactamase Beta-lactamase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.2.6 3.5.2.6] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2G2W OCA].  

[[Category: Berger, J M.]]

[[Category: Bethel, C R.]]

[[Category: Bonomo, R A.]]

[[Category: Corbett, K D.]]

[[Category: Handel, T M.]]

[[Category: Kirsch, J F.]]

[[Category: Reynolds, K A.]]

[[Category: Thomson, J M.]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:27:34 2008''