YadA adhesin

The repeat sequences in solenoid proteins are often so imperfect that it is difficult to identify them without knowledge of the 3D structure or other supplementary information. In highly regular /1-solenoids, such as antifreeze proteins (Leinala et al., 2002 Liou et al., 2000) or YadA adhesin (Nummelin et al., 2004), the repeats are of the same length and sequence similarity between the repeats is discernible (so-called overt repeats). Frequently, however, the repeats in a given /1-solenoid vary in length because additional residues may be inserted at turn sites without disrupting the pattern of /1-strands that stabilizes the structure (Steinbacher et al., 1994 Yoder et al., 1993). In these cases, the structural repeats are not apparent as sequence repeats (covert repeats). 

Nummelin, H., Merckel, M. C., Leo, J. C., Lankinen, H., Skurnik, M., and Goldman, A. (2004). The Yersinia adhesin YadA collagen-binding domain structure is a novel left-handed parallel beta-roll. EMBOJ. 23, 701-711. 

Hoiczyk, E., Roggenkamp, A., Reichenbecher, M., Lupas, A., and Heesemann, J. (2000). Structure and sequence analysis of Yersinia YadA and Moraxella UspAs reveal a novel class of adhesins. EMBO J. 19, 5989-5999. 

A common enteropathogenic yersinias adhesin, yadA, in fact was the first antivirulence gene described in Y. pestis [25], It has been shown that the yadA gene in Y. pestis has suffered a point mutation leading to a frameshift and its inactivation. Moreover, yadA complementation in Y. pestis with a wild type allele leads to its virulence attenuation, which proves an antivirulence character of the yadA gene in Y. pestis. 

Endosialidases have been engineered to bind specifically o2,8-linked polysialic acid as inactive variants for fluorescence microscopy [69, 105, 168]. The endosialidase gene of the mutant phage K1A2 has been fused to green fluorescent protein (GFP). A repeat part of the Yersinia enterocolitica adhesin (yadA) stalk [199] was added between the endosialidase and GFP to increase the yield of soluble protein. A fusion protein containing the catalytically active form of the endosialidase prepared for control was negative [168]. 

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