OmpA-like transmembrane domain explained

OmpA-like transmembrane domain is an evolutionarily conserved domain of bacterial outer membrane proteins. This domain consists of an eight-stranded beta barrel.^[1] OmpA is the predominant cell surface antigen in enterobacteria found in about 100,000 copies per cell.^[2] The expression of OmpA is tightly regulated by a variety of mechanisms. One mechanism by which OmpA expression is regulated in Vibrio species is by an antisense non-coding RNA called VrrA.^[3]

Structure

The structure consists of an eight-stranded Up-And-Down Beta-Barrel. The strands are connected by four extracellular loops and three intracellular turns.^[4]

Function

Numerous OmpA-like membrane-spanning domains contribute to bacterial virulence by a variety of mechanisms such as binding to host cells or immune regulators such as Factor H. Notable examples include E. coli OmpA and Yersinia pestis Ail. Several of these proteins are vaccine candidates.

E. coli OmpA was shown to make specific interactions with the human glycoprotein Ecgp on brain microvascular endothelial cells.^[5] Cronobacter sakazakii is a food borne pathogen causing meningitis in neonates and was shown to bind fibronectin via OmpA and this played a significant role in invasion of the blood brain barrier.^[6] The Y. pestis protein Ail binds to laminin and heparin, therefore allowing bacterial attachment to host cells.^[7] The Borrelia afzelii protein BAPKO_0422, is an OmpA-like transmembrane domain and binds to human Factor H.^[8]

See also

• OmpA domain

Notes and References

1. Pautsch A, Schulz GE . Structure of the outer membrane protein A transmembrane domain . Nature Structural Biology . 5 . 11 . 1013–7 . Nov 1998 . 9808047 . 10.1038/2983 . 20529728 .
2. Smith SG, Mahon V, Lambert MA, Fagan RP . A molecular Swiss army knife: OmpA structure, function and expression . FEMS Microbiology Letters . 273 . 1 . 1–11 . Aug 2007 . 17559395 . 10.1111/j.1574-6968.2007.00778.x . free .
3. Song T, Wai SN . A novel sRNA that modulates virulence and environmental fitness of Vibrio cholerae . RNA Biology . 6 . 3 . 254–8 . July 2009 . 19411843 . 10.4161/rna.6.3.8371 . free .
4. Fernández C, Hilty C, Wider G, Güntert P, Wüthrich K . NMR structure of the integral membrane protein OmpX . Journal of Molecular Biology . 336 . 5 . 1211–21 . Mar 2004 . 15037080 . 10.1016/j.jmb.2003.09.014 .
5. Prasadarao NV, Srivastava PK, Rudrabhatla RS, Kim KS, Huang SH, Sukumaran SK . Cloning and expression of the Escherichia coli K1 outer membrane protein A receptor, a gp96 homologue . Infection and Immunity . 71 . 4 . 1680–8 . Apr 2003 . 12654781 . 152083 . 10.1128/IAI.71.4.1680-1688.2003 .
6. Nair MK, Venkitanarayanan K, Silbart LK, Kim KS . Outer membrane protein A (OmpA) of Cronobacter sakazakii binds fibronectin and contributes to invasion of human brain microvascular endothelial cells . Foodborne Pathogens and Disease . 6 . 4 . 495–501 . May 2009 . 19415974 . 10.1089/fpd.2008.0228 .
7. Yamashita S, Lukacik P, Barnard TJ, Noinaj N, Felek S, Tsang TM, Krukonis ES, Hinnebusch BJ, Buchanan SK . Structural insights into Ail-mediated adhesion in Yersinia pestis . Structure . 19 . 11 . 1672–82 . Nov 2011 . 22078566 . 3217190 . 10.1016/j.str.2011.08.010 .
8. Dyer A, Brown G, Stejskal L, Laity PR, Bingham RJ . The Borrelia afzelii outer membrane protein BAPKO_0422 binds human factor-H and is predicted to form a membrane-spanning β-barrel . Bioscience Reports . 35 . 4 . 2015 . 26181365 . 10.1042/BSR20150095 . 4613713 . e00240.