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RATIONAL DESIGN OF A CALCIUM-BINDING ADHESION PROTEIN NMR, 20 STRUCTURES
Structural highlights
FunctionCD2_RAT CD2 interacts with lymphocyte function-associated antigen (LFA-3) and CD48/BCM1 to mediate adhesion between T-cells and other cell types. CD2 is implicated in the triggering of T-cells, the cytoplasmic domain is implicated in the signaling function. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCa2+, "a signal of life and death", controls numerous cellular processes through interactions with proteins. An effective approach to understanding the role of Ca2+ is the design of a Ca2+-binding protein with predicted structural and functional properties. To design de novo Ca2+-binding sites in proteins is challenging due to the high coordination numbers and the incorporation of charged ligand residues, in addition to Ca2+-induced conformational change. Here, we demonstrate the successful design of a Ca2+-binding site in the non-Ca2+-binding cell adhesion protein CD2. This designed protein, Ca.CD2, exhibits selectivity for Ca2+ versus other di- and monovalent cations. In addition, La3+ (Kd 5.0 microM) and Tb3+ (Kd 6.6 microM) bind to the designed protein somewhat more tightly than does Ca2+ (Kd 1.4 mM). More interestingly, Ca.CD2 retains the native ability to associate with the natural target molecule. The solution structure reveals that Ca.CD2 binds Ca2+ at the intended site with the designed arrangement, which validates our general strategy for designing de novo Ca2+-binding proteins. The structural information also provides a close view of structural determinants that are necessary for a functional protein to accommodate the metal-binding site. This first success in designing Ca2+-binding proteins with desired structural and functional properties opens a new avenue in unveiling key determinants to Ca2+ binding, the mechanism of Ca2+ signaling, and Ca2+-dependent cell adhesion, while avoiding the complexities of the global conformational changes and cooperativity in natural Ca2+-binding proteins. It also represents a major achievement toward designing functional proteins controlled by Ca2+ binding. Design of a calcium-binding protein with desired structure in a cell adhesion molecule.,Yang W, Wilkins AL, Ye Y, Liu ZR, Li SY, Urbauer JL, Hellinga HW, Kearney A, van der Merwe PA, Yang JJ J Am Chem Soc. 2005 Feb 23;127(7):2085-93. PMID:15713084[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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