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Designed ankyrin repeat protein (DARPin) binders to AcrB: Plasticity of the Interface
Structural highlights
FunctionACRB_ECOLI AcrAB is a drug efflux protein with a broad substrate specificity.[1] [2] [3] Publication Abstract from PubMedThe formation of well-diffracting crystals is a major bottleneck in structural analysis of membrane proteins by X-ray crystallography. One approach to improve crystal quality is the use of DARPins as crystallization chaperones. Here, we present a detailed analysis of the interaction between DARPins and the integral membrane protein AcrB. We find that binders selected in vitro by ribosome display share a common epitope. The comparative analysis of three crystal structures of AcrB-DARPin complexes allowed us to study the plasticity of the interaction with this dominant binding site. Seemingly redundant AcrB-DARPin crystals show substantially different diffraction quality as a result of subtle differences in the binding geometry. This work exemplifies the importance to screen a number of crystallization chaperones to obtain optimal diffraction data. Crystallographic analysis is complemented by biophysical characterization of nine AcrB binders. We observe that small variations in the interface can lead to differing behavior of the DARPins with regards to affinity, stoichiometry of the complexes and specificity for their target. Designed ankyrin repeat protein binders for the crystallization of AcrB: Plasticity of the dominant interface.,Monroe N, Sennhauser G, Seeger MA, Briand C, Grutter MG J Struct Biol. 2011 May;174(2):269-81. Epub 2011 Feb 4. PMID:21296164[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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