Cellulose, an aggregate of unbranched polymers of beta-1,4-linked glucose residues, is the major component of wood and thus paper, and is synthesised by plants, most algae, some bacteria and fungi, and even some animals. The genes that synthesise cellulose in higher plants differ greatly from the well-characterised genes found in Acetobacter and Agrobacterium sp. More correctly designated as 'cellulose synthase catalytic subunits', plant cellulose synthase (CesA) proteins are integral membrane proteins, approximately 1,000 amino acids in length. There are a number of highly conserved residues, including several motifs shown to be necessary for processive glycosyltransferase activity [1].

1: Higher plants contain homologs of the bacterial celA genes encoding the catalytic subunit of cellulose synthase. Pear JR, Kawagoe Y, Schreckengost WE, Delmer DP, Stalker DM; Proc Natl Acad Sci U S A 1996;93:12637-12642. PMID:8901635

2: Higher plant cellulose synthases. Richmond T; Genome Biol 2000;1:1-6. PMID:11178255