1MQ1

Ca2+-S100B-TRTK-12 complex

Summary for 1MQ1

• Entry DOI: 10.2210/pdb1mq1/pdb
• Related: 1UWO
• Descriptor: S-100 protein, beta chain, F-actin capping protein alpha-1 subunit (2 entities in total)
• Functional Keywords: protein-peptide complex, ef-hand, metal binding protein
• Biological source: Homo sapiens (human); More
• Cellular location: Cytoplasm: P04271; Cytoplasm, cytoskeleton (By similarity): P52907
• Total number of polymer chains: 4
• Total formula weight: 24147.14

Authors

McClintock, K.A.,Shaw, G.S. (deposition date: 2002-09-13, release date: 2002-12-25, Last modification date: 2024-05-22)

Primary citation

McClintock, K.A.,Shaw, G.S.
A novel S100 target conformation is revealed by the solution structure of the Ca2+-S100B-TRTK-12 complex.
J.Biol.Chem., 278:6251-6257, 2003

PubMed Abstract: The Alzheimer-linked neural protein S100B is a signaling molecule shown to control the assembly of intermediate filament proteins in a calcium-sensitive manner. Upon binding calcium, a conformational change occurs in S100B exposing a hydrophobic surface for target protein interactions. The synthetic peptide TRTK-12 (TRTKIDWNKILS), derived from random bacteriophage library screening, bears sequence similarity to several intermediate filament proteins and has the highest calcium-dependent affinity of any target molecule for S100B to date (K(d) <1 microm). In this work, the three-dimensional structure of the Ca(2+)-S100B-TRTK-12 complex has been determined by NMR spectroscopy. The structure reveals an extended, contiguous hydrophobic surface is formed on Ca(2+)-S100B for target interaction. The TRTK-12 peptide adopts a coiled structure that fits into a portion of this surface, anchored at Trp(7), and interacts with multiple hydrophobic contacts in helices III and IV of Ca(2+)-S100B. This interaction is strikingly different from the alpha-helical structures found for other S100 target peptides. By using the TRTK-12 interaction as a guide, in combination with other available S100 target structures, a recognition site on helix I is identified that may act in concert with the TRTK-12-binding site from helices III and IV. This would provide a larger, more complex site to interact with full-length target proteins and would account for the promiscuity observed for S100B target protein interactions.

PubMed: 12480931
DOI: 10.1074/jbc.M210622200

Experimental method

SOLUTION NMR