1cq4 is a 2 chain structure with sequence from Hordeum vulgare. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
We have constructed mutants of chymotrypsin inhibitor 2 with short glutamine repeats inserted into its inhibitory loop. These mutants oligomerize when expressed in Escherichia coli. The dimer of a mutant with four glutamines now has been crystallized, and its structure has been solved by molecular replacement by using the wild-type monomer as a search model. The structure of each half of the dimer is found to be the same as that of the wild-type monomer, except around the glutamine insertion. It was proposed that the components of the oligomers are held together by hydrogen bonds between the main-chain and side-chain amides of the glutamine repeats. Instead, they appear to form by swapping domains on folding in E. coli, and the glutamine repeats connecting the components of the dimers are disordered.
Crystal structure of a dimeric chymotrypsin inhibitor 2 mutant containing an inserted glutamine repeat.,Chen YW, Stott K, Perutz MF Proc Natl Acad Sci U S A. 1999 Feb 16;96(4):1257-61. PMID:9990011[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
↑ Chen YW, Stott K, Perutz MF. Crystal structure of a dimeric chymotrypsin inhibitor 2 mutant containing an inserted glutamine repeat. Proc Natl Acad Sci U S A. 1999 Feb 16;96(4):1257-61. PMID:9990011
