3wxa
X-ray crystal structural analysis of the complex between ALG-2 and Sec31A peptide
Structural highlights
FunctionPDCD6_HUMAN Calcium-binding protein required for T-cell receptor-, Fas-, and glucocorticoid-induced cell death. May mediate Ca(2+)-regulated signals along the death pathway (By similarity). Calcium-dependent adapter necessary for the association between PDCD6IP and TSG101. Interaction with DAPK1 can accelerate apoptotic cell death by increasing caspase-3 activity.[1] [2] Publication Abstract from PubMedALG-2, a 22-kDa penta-EF-hand protein, is involved in cell death, signal transduction, membrane trafficking, etc., by interacting with various proteins in mammalian cells in a Ca2+-dependent manner. Most known ALG-2-interacting proteins contain proline-rich regions in which either PPYPXnYP (type 1 motif) or PXPGF (type 2 motif) is commonly found. Previous X-ray crystal structural analysis of the complex between ALG-2 and an ALIX peptide revealed that the peptide binds to the two hydrophobic pockets. In the present study, we resolved the crystal structure of the complex between ALG-2 and a peptide of Sec31A (outer shell component of coat complex II, COPII; containing the type 2 motif) and found that the peptide binds to the third hydrophobic pocket (Pocket 3). While amino acid substitution of Phe85, a Pocket 3 residue, with Ala abrogated the interaction with Sec31A, it did not affect the interaction with ALIX. On the other hand, amino acid substitution of Tyr180, a Pocket 1 residue, with Ala caused loss of binding to ALIX, but maintained binding to Sec31A. We conclude that ALG-2 recognizes two types of motifs at different hydrophobic surfaces. Furthermore, based on the results of serial mutational analysis of the ALG-2-binding sites in Sec31A, the type 2 motif was newly defined. Structural Analysis of the Complex between Penta-EF-Hand ALG-2 Protein and Sec31A Peptide Reveals a Novel Target Recognition Mechanism of ALG-2.,Takahashi T, Kojima K, Zhang W, Sasaki K, Ito M, Suzuki H, Kawasaki M, Wakatsuki S, Takahara T, Shibata H, Maki M Int J Mol Sci. 2015 Feb 6;16(2):3677-99. doi: 10.3390/ijms16023677. PMID:25667979[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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