Structural Relationships among the Blue Copper Oxidases

structural Relationships among the Blue Copper Oxidases 

Knowledge of the three-dimensional structure of ascorbate oxidase and of amino-acid sequences of all members of the blue oxidases made it possible to carry out a structurally based amino-acid sequence alignment 101) involving N. crassa laccase, cucumber ascorbate oxidase, and human ceruloplasmin. The structural basis of this alignment was 

Two other SS bridges in ceruloplasmin, 257-338 and 618-699, are similar to 41-124 and 424-525 of ascorbate oxidase. Also these disulfide bridges can be formed easily. 

The tryptic cleavage sites for ceruloplasmin are at the end of the domains but approximately follow the internal triplication. A fourth cleavage site is in the middle of domain 3 in an extended and variable 

About 40% (938 residues) of the amino-acid sequence of factor V has been established (103). It shows similarities to the amino-acid sequences of human ceruloplasmin and human factor VIII. The partial sequence contains a region that is similar to domains 5 and 6 in ceruloplasmin and A3 in factor VIII. However, it does not have the canonical ligands for type-1 copper or the trinuclear copper site. On the other hand, cysteine residues are present at the homologous position of ceruloplasmin. They form a disulfide bridge in this structure. 

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V. structural Relationships among the Blue Copper Oxidases... 

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