Protein Domain : Closterovirus 1a polyprotein, central region IPR040910

Type	Family
Description	This family represents an alignment of the Zemlya region of closteroviruses. The alignment of the 1a polyprotein of the Closteroviridae family members revealed that this region was not conserved in other genera. The homologs of the Zemlya region are not found in other viral or cellular proteins. This region is named "the Zemlya region"(zemlya)- is the Russian word for "earth", meaning that its conserved amino acid sequence represents a solid ground within the highly variable central region of 1a polyporotein. It is composed of four predicted α-helices, alphaA to alphaD, and contains three conserved positions: i) a strictly conserved glutamate (E) in helix alphaA (E1291 in Beet yellows closterovirus (BYV)); ii) a strictly conserved proline (P1380) in alphaD; and iii) a conserved basic position (arginine or lysine; R1384 in BYV). The presence of a conserved proline in helix alphaD is noteworthy because prolines are strongly disfavoured in helices; this proline most probably induces a kink in the helix. Functional studies have suggested that most part of the Zemlya region, targets the ER and remodels the ER membranes. More specifically, deletion analysis and substitutions of the conserved hydrophobic amino acid residues suggest a role of the putative amphipathic helix1368-1385 (alphaD) in the formation of globules. Hence it was proposed that this specific region in 1a protein protein may be involved in the biogenesis of closterovirus [ ].
Short Name	Zemlya