Protein Family Models

T6SSs are toxin delivery systems. It is a multiprotein complex requiring numerous core proteins (Tss proteins) including cytoplasmic, transmembrane, and outer membrane components. The needle or tube apparatus is comprised of a phage-like complex, similar to the T4 contractile bacteriophage tail, which is thought to be anchored to the membrane by a trans-envelope complex [1]. VipA is a family of Gram-negative bacterial proteins that form part of the type VI pathogenic secretion system. Members have been variously defined as VC_A0107 family, Hcp2, TssB and VipA, for ClpV-interacting proteins. VipB and VipA proteins interact very closely to form the shaft of the pathogenic penetrating needle system [2,3,4]. VipA and VipB (TssB and TssC) proteins were shown to form a cog-wheel like tubular structure in V. cholerae that was noticed to resemble T4 phage gp18 polysheath. Two beta-strands of VipA and four beta-strands of VipB intertwine forming the middle layer of the sheath. The sheath assembles around an inner Hcp tube and is attached to a structure called a baseplate that spans the bacterial membranes. Importantly, VipA/VipB sheath was shown to form a long contractile organelle in V. cholerae and in E. coli, suggesting that sheath contraction powers the secretion [5]. [1]. 26768901. Type VI secretion systems of human gut Bacteroidales segregate into three genetic architectures, two of which are contained on mobile genetic elements. Coyne MJ, Roelofs KG, Comstock LE;. BMC Genomics. 2016;17:58. [2]. 1913969. [Study on BCG vaccination and incidence of children's tuberculous meningitis in Liaoning province]. Wu QR;. Zhonghua Jie He. TRUNCATED at 1650 bytes (from Pfam)

Date:

2024-10-16

Work by Mougous, et al. (2006), describes IAHP-related loci as a type VI secretion system (PMID:16763151). This protein family is associated with type VI secretion loci, although not treated explicitly by Mougous, et al.

Gene:

tssB

Date:

2024-08-07

type VI secretion system contractile sheath small subunit TssB/VipA assembles with the large subunit TssC/VipB to form tubules that conserve structural/functional homology with tail sheaths of contractile bacteriophages and pyocins

Date:

2018-07-30