An Ionizable Active-Site Tryptophan Imparts Catalase Activity to a Peroxidase Core

作者:Loewen Peter C; Carpena Xavi; Vidossich Pietro; Fita Ignacio*; Rovira Carme
来源:Journal of the American Chemical Society, 2014, 136(20): 7249-7252.
DOI:10.1021/ja502794e

摘要

Catalase peroxidases (KatG%26apos;s) are bifunctional heme proteins that can disproportionate hydrogen peroxide (catalatic reaction) despite their structural dissimilarity with monofunctional catalases. Using X-ray crystallography and QM/MM calculations, we demonstrate that the catalatic reaction of KatG%26apos;s involves deprotonation of the active-site Trp, which plays a role similar to that of the distal His in monofunctional catalases. The interaction of a nearby mobile arginine with the distal Met-Tyr-Trp essential adduct (in/out) acts as an electronic switch, triggering deprotonation of the adduct Trp.

  • 出版日期2014-5-21