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The Gas family of proteins of Saccharomyces cerevisiae : characterization and evolutionary analysis
Author(s) -
Ragni Enrico,
Fontaine Thierry,
Gissi Carmela,
Latgè Jean Paul,
Popolo Laura
Publication year - 2007
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.1473
Subject(s) - biology , saccharomyces cerevisiae , subfamily , biochemistry , phylogenetic tree , yeast , protein family , gene family , gene , c terminus , genetics , amino acid , gene expression
The GAS multigene family of Saccharomyces cerevisiae is constituted by five genes ( GAS1–GAS5 ), but GAS1 was the only one to have been characterized to date. Gas1 is a glycosylphosphatidylinositol‐anchored protein predominantly localized in the plasma membrane and is also a representative of family GH72 of glycosidase/transglycosidases, a wide group of yeast and fungal enzymes involved in cell wall assembly. Gas1–Gas5 proteins share a common N‐terminal domain but exhibit different C‐terminal extensions, in which a domain named Cys‐Box is located. This domain is similar to the carbohydrate binding module 43 and is present only in Gas1p and Gas2p. Here we report the expression in P. pastoris of soluble forms of Gas proteins. Gas1, 2, 4 and 5 proteins were secreted with a yield of about 30‐40 mg/l of medium, whereas the yield for Gas3p was about three times lower. Gas proteins proved to be N‐glycosylated. Purified Gas proteins were tested for enzymatic activity. Gas2, Gas4 and Gas5p showed a β‐(1,3)‐glucanosyltransferase activity similar to Gas1p. A phylogenetic tree of the N‐terminal regions of family GH72 members was constructed. Two subfamilies of N‐terminal regions were distinguished: one subfamily, GH72 + , contains proteins that possess a Cys‐box in the C‐terminal region, whereas family GH72 − comprises proteins that lack a Cys‐box. On the basis of this net distinction, we speculate that the type of C‐tail region imposed constraints to the evolution of the N‐terminal portion. Copyright © 2007 John Wiley & Sons, Ltd.