title: Identification and rational redesign of peptide ligands to CRIP1, a novel biomarker for cancers.
abstract: Cysteine-rich intestinal protein 1 (CRIP1) has been identified as a novel marker for early detection of cancers. Here we report on the use of phage display in combination with molecular modeling to identify a high-affinity ligand for CRIP1. Panning experiments using a circularized C7C phage library yielded several consensus sequences with modest binding affinities to purified CRIP1. Two sequence motifs, A1 and B5, having the highest affinities for CRIP1, were chosen for further study. With peptide structure information and the NMR structure of CRIP1, the higher-affinity A1 peptide was computationally redesigned, yielding a novel peptide, A1M, whose affinity was predicted to be much improved. Synthesis of the peptide and saturation and competitive binding studies demonstrated approximately a 10-28-fold improvement in the affinity of A1M compared to that of either A1 or B5 peptide. These techniques have broad application to the design of novel ligand peptides.
authors.affiliation: Department of Radiology, Case Western Reserve University, Cleveland, Ohio, United States of America.
authors.forename: Jihua
authors.initials: J
authors.lastname: Hao
authors.forename: Adrian W R
authors.initials: AW
authors.lastname: Serohijos
authors.forename: Gail
authors.initials: G
authors.lastname: Newton
authors.forename: Gina
authors.initials: G
authors.lastname: Tassone
authors.forename: Zuncai
authors.initials: Z
authors.lastname: Wang
authors.forename: Dennis C
authors.initials: DC
authors.lastname: Sgroi
authors.forename: Nikolay V
authors.initials: NV
authors.lastname: Dokholyan
authors.forename: James P
authors.initials: JP
authors.lastname: Basilion
mesh_terms: D020816:Amino Acid Motifs; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000819:agonists* / Q000037:antagonists & inhibitors*; D003090:Coliphages; D019295:Computational Biology / Q000379:methods*; D006801:Humans; D060588:LIM Domain Proteins; D008024:Ligands; D008958:Models, Molecular; D019151:Peptide Library; D010455:Peptides / Q000032:analysis / Q000138:chemical synthesis / Q000737:chemistry; D011485:Protein Binding; D013816:Thermodynamics
chemical_list: C486181:CRIP1 protein, human; D002352:Carrier Proteins; D060588:LIM Domain Proteins; D008024:Ligands; D019151:Peptide Library; D010455:Peptides