4w4h

Publication Abstract from PubMed

Two crystal forms of Escherichia coli tryptophanase (tryptophan indole-lyase, Trpase) were obtained under the same crystallization conditions. Both forms belonged to the same space group P43212 but had slightly different unit-cell parameters. The holo crystal form, with pyridoxal phosphate (PLP) bound to Lys270 of both polypeptide chains in the asymmetric unit, diffracted to 2.9 A resolution. The second crystal form diffracted to 3.2 A resolution. Of the two subunits in the asymmetric unit, one was found in the holo form, while the other appeared to be in the apo form in a wide-open conformation with two sulfate ions bound in the vicinity of the active site. The conformation of all holo subunits is the same in both crystal forms. The structures suggest that Trpase is flexible in the apo form. Its conformation partially closes upon binding of PLP. The closed conformation might correspond to the enzyme in its active state with both cofactor and substrate bound in a similar way as in tyrosine phenol-lyase.

Structures of Escherichia coli tryptophanase in holo and `semi-holo' forms.,Kogan A, Raznov L, Gdalevsky GY, Cohen-Luria R, Almog O, Parola AH, Goldgur Y Acta Crystallogr F Struct Biol Commun. 2015 Mar 1;71(Pt 3):286-90. doi:, 10.1107/S2053230X15000850. Epub 2015 Feb 19. PMID:25760702^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.