Open AccessBiosynthesis of a 3,6‐dideoxyhexose: crystallization and X‐ray diffraction of CDP‐6‐deoxy‐ l ‐ threo ‐ d ‐ glycero ‐4‐hexulose‐3‐dehydrase (E 1 ) for ascarylose biosynthesis
Author(s) -
Smith Peter,
Lin Ava,
Szu Pinghui,
Liu Hungwen,
Tsai ShiouChuan
Publication year - 2006
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309106003721
Subject(s) - chemistry , stereochemistry , dimer , biosynthesis , cofactor , enzyme , reductase , crystallization , crystallography , biochemistry , organic chemistry
CDP‐6‐deoxy‐ l ‐ threo ‐ d ‐ glycero ‐4‐hexulose‐3‐dehydrase (E 1 ), along with its reductase (E 3 ), catalyzes the unusual C‐3 deoxygenation of CDP‐6‐deoxy‐ l ‐ threo ‐ d ‐ glycero ‐4‐hexulose to form CDP‐3,6‐dideoxy‐ l ‐ threo ‐ d ‐ glycero ‐4‐hexulose in CDP‐ascarylose biosynthesis [Chen et al. (1996), Biochemistry , 35 , 16412–16420]. This dimeric [2Fe–2S] protein, cloned from the bacteria Yersinia pseudotuberculosis , is currently the only known example of an enzyme that uses a vitamin B 6 ‐derived pyridoxamine 5′‐phosphate (PMP) cofactor to carry out one‐electron chemistry [Agnihotri & Liu (2001), Bioorg. Chem. 29 , 234–257]. It also exhibits a [2Fe–2S] cluster‐binding motif (C‐ X 57 ‐C‐ X 1 ‐C‐ X 7 ‐C) which has not been observed previously [Agnihotri et al. (2004), Biochemistry , 43 , 14265–14274] The recombinant 97.7 kDa dimer was crystallized in the trigonal space group P 3 2 , with unit‐cell parameters a = b = 97.37, c = 142.2 Å, α = β = 90, γ = 120°. A data set has been collected to 1.9 Å resolution. A full MAD data set was also collected at the iron absorption edge that diffracted to 2.0 Å.