CHAPTER 36, FIG URE 4 Proteinase domains of serine proteinases trypsin and thrombin. The active site

a m in o

a c id resid u es

(sh o w n a s sp a ce-fillin g stru ctu res)

are Ser195 (shown in white); His57 (shown in blue), and Asp102

(shown in red). The

sp ec ific ity

pocket residue is Asp189. Both trypsin, the reference serine proteinase, and thrombin

are shown as cartoons with the secondary structure elements marked as defined in the coordinate files for the struc-

tures from the Protein Data Bank. The color scheme is that of R. Sayle, the creator of RasMol, the program used to

produce these ribbon diagrams. Some of the functionally significant differences in thrombin are the residues in the

helix above the catalytic triad and two ligand binding regions, exosites I and II (not shown).

EGF-Like Domains

Prothrombin Kringle 1

Factor X

plus helix

CHAPTER 36, FIG URE 5 Motif structures within coagulation proteins. Common motifs are found in the amino

terminal regions of the proteinase precursor molecules. Shown are the kringle motifs and EGF-like motifs found in

the vitamin K-dependent proteins and in plasminogen. Fibronectin (types I and II) motifs and “apple” motifs (named

from their two-dimensional representations) are also present but not shown. Some epidermal growth factor-like

domains contain |3-hydroxylated Asp residues. The cartoon structures for the motifs are derived from three-dimen-

sional structures determined by x-ray crystallography or by two-dimensional NMR spectroscopy.