title: Structure of the cysteine-rich intestinal protein, CRIP.
abstract: LIM domains are Zn-binding arrays found in a number of proteins involved in the control of cell differentiation, including several developmentally regulated transcription factors and a human proto-oncogene product. The rat cysteine-rich intestinal protein, CRIP, is a 76-residue polypeptide which contains a LIM motif. The solution structure of CRIP has been determined by homonuclear and 1H-15N heteronuclear correlated nuclear magnetic resonance spectroscopy. Structures with individual distance violations of < or = 0.03 angstrom and penalties (squared sum of distance violations) of < or = 0.06 angstrom2 were generated with a total of 500 nuclear Overhauser effect (NOE)-derived distance restraints (averaging 15.6 restraints per refined residue). Superposition of backbone heavy atoms of ordered residues relative to mean atom positions is achieved with pairwise rms deviations of 0.54(+/-0.14) angstrom. As observed previously for a peptide with the sequence of the C-terminal LIM domain from the avian cysteine-rich protein, CRP (cCRP-LIM2), CRIP binds two equivalents of zinc, forming N-terminal CCHC (Cys3, Cys6, His24, Cys27) and C-terminal CCCC (Cys30, Cys33, Cys51, Cys55) modules. The CCHC and CCCC modules in CRIP contain two orthogonally-arrayed antiparallel beta-sheets. The C-terminal end of the CCHC module contains a tight turn and the C terminus of the CCCC module forms an alpha-helix. The modules pack via hydrophobic interactions, forming a compact structure that is similar to that observed for cCRP-LIM2. The most significant differences between the structures occur at the CCHC module-CCCC module interface, which results in a difference in the relative orientations of the modules, and at the C terminus where the alpha-helix appears to be packed more tightly against the preceding antiparallel beta-sheet. The greater abundance of NOE information obtained for CRIP relative to cCRP-LIM2, combined with the analysis of J-coupling and proton chemical shift data, have allowed a more detailed evaluation of the molecular level interactions that stabilize the fold of the LIM motif.
authors.affiliation: Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Maryland Baltimore County 21228, USA.
authors.forename: G C
authors.initials: GC
authors.lastname: Pérez-Alvarado
authors.forename: J L
authors.initials: JL
authors.lastname: Kosa
authors.forename: H A
authors.initials: HA
authors.lastname: Louis
authors.forename: M C
authors.initials: MC
authors.lastname: Beckerle
authors.forename: D R
authors.initials: DR
authors.lastname: Winge
authors.forename: M F
authors.initials: MF
authors.lastname: Summers
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry*; D060588:LIM Domain Proteins; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011506:Proteins; D000090063:Proto-Oncogene Mas; D051381:Rats
chemical_list: C486181:CRIP1 protein, human; D002352:Carrier Proteins; C071434:Crip1 protein, rat; D060588:LIM Domain Proteins; C000715470:MAS1 protein, human; D011506:Proteins; D000090063:Proto-Oncogene Mas