5b2h

Publication Abstract from PubMed

Clostridium botulinum produces a large toxin complex (L-TC) comprising botulinum neurotoxin associated with auxiliary nontoxic proteins. A complex of 33- and 17-kDa hemagglutinins (an HA-33/HA-17 trimer) enhances L-TC transport across the intestinal epithelial cell layer via binding HA-33 to a sugar on the cell surface. At least two subtypes of serotype C/D HA-33 exhibit differing preferences for the sugars sialic acid and galactose. Here, we compared the three-dimensional structures of the galactose-binding HA-33 and HA-33/HA-17 trimers produced by the C-Yoichi strain. Comparisons of serotype C/D HA-33 sequences reveal a variable region with relatively low sequence similarity across the C. botulinum strains; the variability of this region may influence the manner of sugar-recognition by HA-33. Crystal structures of sialic acid- and galactose-binding HA-33 are broadly similar in appearance. However, small-angle X-ray scattering revealed distinct solution structures for HA-33/HA-17 trimers. A structural change in the C-terminal variable region of HA-33 might cause a dramatic shift in the conformation and sugar-recognition mode of HA-33/HA-17 trimer.

Conformational divergence in the HA-33/HA-17 trimer of serotype C and D botulinum toxin complex.,Sagane Y, Hayashi S, Akiyama T, Matsumoto T, Hasegawa K, Yamano A, Suzuki T, Niwa K, Watanabe T, Yajima S Biochem Biophys Res Commun. 2016 May 27. pii: S0006-291X(16)30821-X. doi:, 10.1016/j.bbrc.2016.05.113. PMID:27237978^[1]

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