Document Type

Article

Media Type

Text

Abstract

Carbohydrate-active enzyme glycosyltransferase family 8 (GT8) includes the plant galacturonosyltransferase1-related gene family of proven and putative a-galacturonosyltransferase (GAUT) and GAUT-like (GATL) genes. We computationally identified and investigated this family in 15 fully sequenced plant and green algal genomes and in the National Center for Biotechnology Information nonredundant protein database to determine the phylogenetic relatedness of the GAUTs and GATLs to other GT8 family members. The GT8 proteins fall into three well-delineated major classes. In addition to GAUTs and GATLs, known or predicted to be involved in plant cell wall biosynthesis, class I also includes a lower plantspecific GAUT and GATL-related (GATR) subfamily, two metazoan subfamilies, and proteins from other eukaryotes and cyanobacteria. Class II includes galactinol synthases and plant glycogenin-like starch initiation proteins that are not known to be directly involved in cell wall synthesis, as well as proteins from fungi, metazoans, viruses, and bacteria. Class III consists almost entirely of bacterial proteins that are lipooligo/polysaccharide a-galactosyltransferases and a-glucosyltransferases. Sequence motifs conserved across all GT8 subfamilies and those specific to plant cell wall-related GT8 subfamilies were identified and mapped onto a predicted GAUT1 protein structure. The tertiary structure prediction identified sequence motifs likely to represent key amino acids involved in catalysis, substrate binding, protein-protein interactions, and structural elements required for GAUT1 function. The results show that the GAUTs, GATLs, and GATRs have a different evolutionary origin than other plant GT8 genes, were likely acquired from an ancient cyanobacterium (Synechococcus) progenitor, and separate into unique subclades that may indicate functional specialization.

DOI

10.1104/pp.110.154229

Publication Date

1-1-2010

Department

Department of Biological Sciences

Sponsorship

This work was supported by the U.S. Department of Energy (grant no. DE–PS02–06ER64304), the National Science Foundation (grant nos. NSF/DBI–0354771, NSF/DEB–0830024, NSF/ITR –IIS–0407204, NSF/DBI–0542119, NSF/CCF0621700, and NSF/ MCB–0646109), and the U.S. Department of Agriculture (grant no. NRI–CREES–2006–35318–17301 and grant no. 2010–65115–20396 from the National Institute of Food and Agriculture). The BioEnergy Science Center was supported by the Office of Biological and Environmental Research in the Department of Energy Office of Science.

ISSN

0032-0889

Language

eng

Publisher

American Society of Plant Biologists

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