Crystal Structure of the R132K:R111L:L121E mutant of Cellular Retinoic Acid Binding Protein Type II In Complex With All-Trans-Retinal At 1.18 Angstroms Resolution
Primary Citation of Related Structures: 2G78, 2G79, 2G7B
PubMed Abstract:
Rational redesign of the binding pocket of Cellular Retinoic Acid Binding Protein II (CRABPII) has provided a mutant that can bind retinal as a protonated Schiff base, mimicking the binding observed in rhodopsin. The reengineering was accomplished through a series of choreographed manipulations to ultimately orient the reactive species (the epsilon-amino group of Lys132 and the carbonyl of retinal) in the proper geometry for imine formation ...
Rational redesign of the binding pocket of Cellular Retinoic Acid Binding Protein II (CRABPII) has provided a mutant that can bind retinal as a protonated Schiff base, mimicking the binding observed in rhodopsin. The reengineering was accomplished through a series of choreographed manipulations to ultimately orient the reactive species (the epsilon-amino group of Lys132 and the carbonyl of retinal) in the proper geometry for imine formation. The guiding principle was to achieve the appropriate Bürgi-Dunitz trajectory for the reaction to ensue. Through crystallographic analysis of protein mutants incapable of forming the requisite Schiff base, a highly ordered water molecule was identified as a key culprit in orienting retinal in a nonconstructive manner. Removal of the ordered water, along with placing reinforcing mutations to favor the desired orientation of retinal, led to a triple mutant CRABPII protein capable of nanomolar binding of retinal as a protonated Schiff base. The high-resolution crystal structure of all-trans-retinal bound to the CRABPII triple mutant (1.2 A resolution) unequivocally illustrates the imine formed between retinal and the protein.
Related Citations:
determining crystal structures of proteins and protein complexes by X-ray crystallography: X-ray crystallographic studies of the mutants of cellular retinoic acid binding protein type II toward designing a mimic of rhodopsin Vaezeslami, S. () Thesis --: --
Organizational Affiliation:
Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
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