Open AccessIdentification of novel protein domain for sialyloligosaccharide binding essential toMycoplasma mobilegliding
Author(s) -
Tasuku Hamaguchi,
Masaru Kawakami,
Hidemitsu Furukawa,
Makoto Miyata
Publication year - 2019
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1093/femsle/fnz016
Subject(s) - glycoconjugate , bacterial adhesin , escherichia coli , binding site , bacteria , biology , binding domain , sialic acid , binding protein , plasma protein binding , biochemistry , fetuin , chemistry , microbiology and biotechnology , biophysics , glycoprotein , genetics , gene
Sialic acids, terminal structures of sialylated glycoconjugates, are widely distributed in animal tissues and are often involved in intercellular recognitions, including some bacteria and viruses. Mycoplasma mobile, a fish pathogenic bacterium, binds to sialyloligosaccharide (SO) through adhesin Gli349 and glides on host cell surfaces. The amino acid sequence of Gli349 shows no similarity to known SO-binding proteins. In the present study, we predicted the binding part of Gli349, produced it in Escherichia coli and proved its binding activity to SOs of fetuin using atomic force microscopy. Binding was detected with a frequency of 10.3% under retraction speed of 400 nm/s and was shown to be specific for SO, as binding events were competitively inhibited by the addition of free 3'-sialyllactose. The histogram of the unbinding forces showed 24 pN and additional peaks. These results suggested that the distal end of Gli349 constitutes a novel sialoadhesin domain and is directly involved in the gliding mechanism of M. mobile.