PssJ Is a Terminal Galactosyltransferase Involved in the Assembly of the Exopolysaccharide Subunit in Rhizobium leguminosarum bv. Trifolii
Małgorzata Marczak , Magdalena Wójcik , Kamil Żebracki , Anna Turska-Szewczuk , Kamila Talarek , Dominika Nowak , Leszek Wawiórka , Marcin Sieńczyk , Agnieszka Łupicka-Słowik , Kamila Bobrek , Marceli Romańczuk , Piotr Koper , Andrzej Mazur
AbstractRhizobium leguminosarum bv. trifolii produces exopolysaccharide (EPS) composed of glucose, glucuronic acid, and galactose residues at a molar ratio 5:2:1. A majority of genes involved in the synthesis, modification, and export of exopolysaccharide are located in the chromosomal Pss-I region. In the present study, a ΔpssJ deletion mutant was constructed and shown to produce EPS lacking terminal galactose in the side chain of the octasaccharide subunit. The lack of galactose did not block EPS subunit translocation and polymerization. The in trans delivery of the pssJ gene restored the production of galactose-containing exopolysaccharide. The mutant was compromised in several physiological traits, e.g., motility and biofilm production. An impact of the pssJ mutation and changed EPS structure on the symbiotic performance was observed as improper signaling at the stage of molecular recognition, leading to formation of a significant number of non-infected empty nodules. Terminal galactosyltransferase PssJ was shown to display a structure typical for the GT-A class of glycosyltransferases and interact with other GTs and Wzx/Wzy system proteins. The latter, together with PssJ presence in soluble and membrane protein fractions indicated that the protein plays its role at the inner membrane interface and as a component of a larger complex.
|Journal series||International Journal of Molecular Sciences, ISSN 1422-0067, (N/A 140 pkt)|
|Publication size in sheets||1.25|
|Keywords in English||exopolysaccharide, glycosyltransferase, Rhizobium, symbiosis|
|ASJC Classification||; ; ; ; ; ; ;|
|License||Journal (articles only); published final; ; with publication|
|Score||= 140.0, 10-02-2021, ArticleFromJournal|
|Publication indicators||= 0; : 2018 = 1.224; : 2018 = 4.183 (2) - 2018=4.331 (5)|
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