2G7B

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

Summary for 2G7B

• Entry DOI: 10.2210/pdb2g7b/pdb
• Related: 2G78 2G79 2G7A
• Descriptor: Cellular retinoic acid-binding protein 2, SODIUM ION, RETINAL, ... (4 entities in total)
• Functional Keywords: crabpii, retinoic acid, retinoids, beta barrel, high resolution, schiff base, protonated schiff base, retinal, transport protein
• Biological source: Homo sapiens (human)
• Cellular location: Cytoplasm: P29373
• Total number of polymer chains: 1
• Total formula weight: 15856.12

Authors

Vaezeslami, S.,Geiger, J.H. (deposition date: 2006-02-27, release date: 2007-04-17, Last modification date: 2025-01-29)

Primary citation

Vasileiou, C.,Vaezeslami, S.,Crist, R.M.,Rabago-Smith, M.,Geiger, J.H.,Borhan, B.
Protein design: reengineering cellular retinoic acid binding protein II into a rhodopsin protein mimic.
J.Am.Chem.Soc., 129:6140-6148, 2007

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. 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.

PubMed: 17447762
DOI: 10.1021/ja067546r

Experimental method

X-RAY DIFFRACTION (1.18 Å)