Structure of Ca2+-bound S100A4 and its interaction with peptides derived from nonmuscle myosin-IIA.

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TitleStructure of Ca2+-bound S100A4 and its interaction with peptides derived from nonmuscle myosin-IIA.
Publication TypeJournal Article
Year of Publication2008
AuthorsMalashkevich, VN, Varney, KM, Garrett, SC, Wilder, PT, Knight, D, Charpentier, TH, Ramagopal, UA, Almo, SC, Weber, DJ, Bresnick, AR
JournalBiochemistry
Volume47
Issue18
Pagination5111-26
Date Published2008 May 6
ISSN1520-4995
KeywordsCalcium, Crystallography, X-Ray, Dimerization, Humans, Models, Molecular, Muscles, Nonmuscle Myosin Type IIA, Nuclear Magnetic Resonance, Biomolecular, Peptide Fragments, Protein Binding, Protein Structure, Quaternary, S100 Proteins, Thermodynamics
Abstract

S100A4, also known as mts1, is a member of the S100 family of Ca2+-binding proteins that is directly involved in tumor invasion and metastasis via interactions with specific protein targets, including nonmuscle myosin-IIA (MIIA). Human S100A4 binds two Ca2+ ions with the typical EF-hand exhibiting an affinity that is nearly 1 order of magnitude tighter than that of the pseudo-EF-hand. To examine how Ca2+ modifies the overall organization and structure of the protein, we determined the 1.7 A crystal structure of the human Ca2+-S100A4. Ca2+ binding induces a large reorientation of helix 3 in the typical EF-hand. This reorganization exposes a hydrophobic cleft that is comprised of residues from the hinge region,helix 3, and helix 4, which afford specific target recognition and binding. The Ca2+-dependent conformational change is required for S100A4 to bind peptide sequences derived from the C-terminal portion of the MIIA rod with submicromolar affinity. In addition, the level of binding of Ca2+ to both EF-hands increases by 1 order of magnitude in the presence of MIIA. NMR spectroscopy studies demonstrate that following titration with a MIIA peptide, the largest chemical shift perturbations and exchange broadening effects occur for residues in the hydrophobic pocket of Ca2+-S100A4. Most of these residues are not exposed in apo-S100A4 and explain the Ca2+ dependence of formation of theS100A4-MIIA complex. These studies provide the foundation for understanding S100A4 target recognition and may support the development of reagents that interfere with S100A4 function.

DOI10.1021/bi702537s
Alternate JournalBiochemistry
PubMed ID18410126
PubMed Central IDPMC2633413
Grant ListCA107331 / CA / NCI NIH HHS / United States
GM069945 / GM / NIGMS NIH HHS / United States
GM58888 / GM / NIGMS NIH HHS / United States
P30CA13330 / CA / NCI NIH HHS / United States
R01 CA107331-03 / CA / NCI NIH HHS / United States
R01 GM058888-09 / GM / NIGMS NIH HHS / United States
R01 GM058888-10 / GM / NIGMS NIH HHS / United States
S10 RR015741-01 / RR / NCRR NIH HHS / United States
S10 RR016812-01 / RR / NCRR NIH HHS / United States
S10 RR023447-01 / RR / NCRR NIH HHS / United States