The crystal structure of pseudoazurin from Alcaligenes faecalis S‐6 determined at 2.9 Å resolution

Abstract
The three‐dimensional structure of pseudoazurin, a single copper‐containing protein from Alcaligenes faecalis strain S‐6, has been determined at 2.9 Å resolution by X‐ray crystallography. The sequences of two other pseudoazurins from Pseudomonas AMl and Achromobacter cycloclastes may also be accommodated in this structure. The structure, an eight‐stranded β‐barrel, resembles closely those of plastocyanin and azurin. It possesses two extra α‐helices at the C‐terminus, whereas azurins have an α‐helical flap in the middle of their sequences.