Three‐dimensional structure topology of the calreticulin P‐domain based on NMR assignment

FEBS Letters

Riek, Roland²  Ellgaard, Lars¹  Wüthrich, Kurt²  Braun, Daniel²  Helenius, Ari¹  Herrmann, Torsten² 

[1] Institut für Biochemie, Eidgenössische Technische Hochschule, Universitätstrasse 16, CH-8092 Zurich, Switzerland;Institut für Molekularbiologie und Biophysik, Eidgenössische Technische Hochschule, CH-8093 Zurich, Switzerland

关键词: Calreticulin;    Nuclear magnetic resonance;    Assignment;    Topology;    CNX;    calnexin;    CRT;    calreticulin;    ER;    endoplasmic reticulum;    NMR;    nuclear magnetic resonance;    NOE;    nuclear Overhauser enhancement;    NTA;    nitrilotriacetic acid;    P-domain;    proline-rich domain;   

DOI  :  10.1016/S0014-5793(00)02382-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Calreticulin (CRT) is an abundant molecular chaperone of the endoplasmic reticulum. Its central, proline-rich P-domain, comprising residues 189–288, contains three copies of each of two repeat sequences (types 1 and 2), which are arranged in a characteristic ‘111222’ pattern. Here we show that the three-dimensional structure of CRT(189–288) contains a single hairpin fold formed by the entire polypeptide chain. The loop at the bottom of the hairpin consists of residues 227–247, and is closed by an anti-parallel β-sheet of residues 224–226 and 248–250. Two additional β-sheets contain residues 207–209 and 262–264, and 190–192 and 276–278. The 17-residue spacing of the β-strands in the N-terminal part of the hairpin and the 14-residue spacing in the C-terminal part reflect the length of the type 1 and type 2 sequence repeats. As a consequence of this topology the peptide segments separating the β-strands in the N-terminal part of the hairpin are likely to form bulges to accommodate the extra residues. These results are based on nearly complete sequence-specific NMR assignments for CRT(189–288), which were obtained using standard NMR techniques with the ¹³C/¹⁵N-labeled protein, and collection of nuclear Overhauser enhancement upper distance constraints.

【 授权许可】

Unknown