9.A.61 The Domain of Unknown Function 3339 (DUF3339) Family
The DUF3339 domain is 68 aas in length. It is predicted to contain two transmembrane domains of 20 and 23 residues each but no cleavable signal peptide. Interestingly, several virus sequences have two tandem copies of the gene (4 predicted TMSs), and several larger proteins (enzymes; structural and regulatory proteins) have the DUF3339 domain either N- or C-terminal to the rest of these proteins. Representative sequences of the protein itself ((9.A.61.1.1 - 1.3) or fused structures (9.A.61.2.1 and 3.1) as well as duplicated viral proteins with 4 TMSs (9.A.61.4.1) are included as family members. Most if not all family members are derived from plants and related organisms.