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1.B.73.  The Capsule Biogenesis/Assembly (CBA) Family 

Many pathogenic bacteria encase themselves in a polysaccharide capsule that provides a barrier to the physical and immunological challenges of the host. The mechanism by which the capsule assembles around the bacterial cell is poorly understood. Wzi, an integral outer-membrane protein from E. coli, has been implicated in the formation of group 1 capsules (Rahn et al. 2003). The 2.6 Å resolution structure of Wzi revealed an 18-stranded β-barrel fold with a novel arrangement of long extracellular loops that blocks the extracellular entrance and a helical bundle that plugs the periplasmic end (Bushell et al. 2013). Mutagenesis experiments showed that specific extracellular loops are required for in vivo capsule assembly. Wzi is a lectin that binds the K30 carbohydrate polymer.  Mutants functionally deficient in vivo show no binding to K30 polymer in vitro.Apparently,  Wzi is a novel outer-membrane lectin that assists in the formation of the bacterial capsule via direct interaction with capsular polysaccharides.

References associated with 1.B.73 family:

Bushell, S.R., I.L. Mainprize, M.A. Wear, H. Lou, C. Whitfield, and J.H. Naismith. (2013). Wzi is an outer membrane lectin that underpins group 1 capsule assembly in Escherichia coli. Structure 21: 844-853. 23623732
Gudeman, H. and T. Dameron. (1989). Role of Hawaii State Hospital in the care of the seriously disabled mentally ill. Hawaii Med J 48: 67-69. 2732040
Rahn, A., K. Beis, J.H. Naismith, and C. Whitfield. (2003). A novel outer membrane protein, Wzi, is involved in surface assembly of the Escherichia coli K30 group 1 capsule. J. Bacteriol. 185: 5882-5890. 13129961
Sachdeva, S., N. Kolimi, S.A. Nair, and T. Rathinavelan. (2016). Key diffusion mechanisms involved in regulating bidirectional water permeation across E. coli outer membrane lectin. Sci Rep 6: 28157. 27320406