4.2.2.8 | isoform HepIII, to 1.6 A resolution. The overall architecture of HepIII belongs to the (alpha/alpha)5 toroid subclass with an N-terminal toroid-like domain and a C-terminal beta-sandwich domain. An elimination mechanism is suggested whereby Asn260 and His464 neutralize the carboxylic group, whereas Tyr314 serves both as a general base in C-5 proton abstraction, and a general acid in a proton donation to reconstitute the terminal hydroxyl group, respectively |
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