Barbara C. Furie

PART II. COMPUTER‐ASSISTED MACROMOLECULAR STRUCTURE GENERATION: EXTENSION OF EXISTING INFORMATION: On the Construction of Computer Models of Proteins by the Extension of Crystallographic Structures

One of the central beliefs of molecular biology is that the sequence of amino acids determines the structure of a p r ~ t e i n . ~ ~ Yet our scientific culture has still to discover many of the rules that specify and govern this relationship. The results of X-ray crystallographic determination of specific proteins have led to an understanding of the taxonomy of protein architecture^.^ The protein sequence fileS which had been growing rather slowly because each amino acid sequence had to be determined by chemical techniques is now growing exponentially because amino acid sequences can be derived from nucleic acid sequencese6 Protein extension attempts to shorten the delay be-

New Perspectives in P-Selectin Biology

P-selectin is a cell adhesion molecule that is an integral membrane protein of the alpha granules of resting platelets 1,2 and the Weibel-Palade bodies of endothelial cells3,4. Stimulation of these cells results in translocation of P-selectin to the plasma membrane where it serves as a receptor for leukocytes5,6. P-selectin is a member of the selectin family of adhesion molecules. It shares a common domain structure with other family members, E-selectin and L-selectin. These proteins contain a lectin domain, an EGF domain, a variable number of concensus repeats, a transmembrane domain, and a cytoplasmic tail7,8,9,10