Protein Domain : Gas vesicle protein GvpA, conserved site IPR018493

Type	Conserved_site
Description	Gas vesicles are small, hollow, gas filled protein structures found in several cyanobacterial and archaebacterial microorganisms []. They allow the positioning of the bacteria at the favourable depth for growth.Gas vesicles are hollow cylindrical tubes, closed by a hollow, conical cap at each end. Both the conical end caps and central cylinder are made up of 4-5 nm wide ribs that run at right angles to the long axis of thestructure. Gas vesicles seem to be constituted of two different protein components, GVPa and GVPc. GVPa, a small protein of about 70 amino acid residues, is the main constituent of gas vesicles and form the essentialcore of the structure. The sequence of GVPa is extremely well conserved. GvpJ and GvpM, two proteins encoded in the cluster of genes required for gas vesicle synthesis in the archaebacteria Halobacterium salinarium andHalobacterium mediterranei (Haloferax mediterranei), have been found [ ] to be evolutionary related to GVPa. The exact functionof these two proteins is not known, although they could be important for determining the shape determination gas vesicles. The N-terminal domain of Aphanizomenon flos-aquae protein GvpA/J is also related to GVPa.This entry represents conserved sequence regions located in the N- and C-terminal domains of these proteins.
Short Name	Gas-vesicle_GvpA_CS