Factor VIIa: Difference between revisions

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===Evolutionary specificity===

All of the serine proteases have a catalytic domain consisting of two β-barrels with the catalytic triad, Ser-His-Asp located at the interface. Five enzyme-substrate hydrogen bonds at positions P1 and P3 are well conserved and serve to position the scissile peptide bond in the correct orientation for an attack by the γ-oxygen of Ser. More distal contacts diverge. The most divergent are the surface loops which control specificity. Serine proteases not only show the divergence of substrate specificity but also examples of convergent evolution. A demonstration of convergent evolution in serine proteases is found in four other folds, besides the chynotrypsin-like fold, with the catalytic triad in similar positions<ref>PMID:879782</ref><

All of the serine proteases have a catalytic domain consisting of two β-barrels with the catalytic triad, Ser-His-Asp located at the interface<ref>PMID:9374470</ref>. Five enzyme-substrate hydrogen bonds at positions P1 and P3 are well conserved and serve to position the scissile peptide bond in the correct orientation for an attack by the γ-oxygen of Ser. More distal contacts diverge. The most divergent are the surface loops which control specificity. Serine proteases not only show the divergence of substrate specificity but also examples of convergent evolution. A demonstration of convergent evolution in serine proteases is found in four other folds, besides the chynotrypsin-like fold, with the catalytic triad in similar positions<ref>PMID:879782</ref>. Mutational experiments have shown that the S1 pocket is important in organization of the substrate for catalysis. In some serine proteases, however, more distant residues play a bigger role<ref>PMID:2716847</ref>.

[[Image:trypsin fold.jpg|left]][[Image:S1 pocket.jpg|right]]

Factor VIIa: Difference between revisions

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@@ Line 46: / Line 46: @@
 ===Evolutionary specificity===
-All of the serine proteases have a catalytic domain consisting of two β-barrels with the catalytic triad, Ser-His-Asp located at the interface. Five enzyme-substrate hydrogen bonds at positions P1 and P3 are well conserved and serve to position the scissile peptide bond in the correct orientation for an attack by the γ-oxygen of Ser. More distal contacts diverge. The most divergent are the surface loops which control specificity. Serine proteases not only show the divergence of substrate specificity but also examples of convergent evolution.  A demonstration of convergent evolution in serine proteases is found in four other folds, besides the chynotrypsin-like fold, with the catalytic triad in similar positions<ref>PMID:879782</ref><
+All of the serine proteases have a catalytic domain consisting of two β-barrels with the catalytic triad, Ser-His-Asp located at the interface<ref>PMID:9374470</ref>. Five enzyme-substrate hydrogen bonds at positions P1 and P3 are well conserved and serve to position the scissile peptide bond in the correct orientation for an attack by the γ-oxygen of Ser. More distal contacts diverge. The most divergent are the surface loops which control specificity. Serine proteases not only show the divergence of substrate specificity but also examples of convergent evolution.  A demonstration of convergent evolution in serine proteases is found in four other folds, besides the chynotrypsin-like fold, with the catalytic triad in similar positions<ref>PMID:879782</ref>. Mutational experiments have shown that the S1 pocket is important in organization of the substrate for catalysis. In some serine proteases, however, more distant residues play a bigger role<ref>PMID:2716847</ref>.
 [[Image:trypsin fold.jpg|left]][[Image:S1 pocket.jpg|right]]