Primary Citation of Related Structures:   3E4B
PubMed Abstract: 
The opportunistic pathogen Pseudomonas aeruginosa causes chronic biofilm infections in cystic fibrosis patients. During colonization of the lung, P. aeruginosa converts to a mucoid phenotype characterized by overproduction of the exopolysaccharide alginate ...
The opportunistic pathogen Pseudomonas aeruginosa causes chronic biofilm infections in cystic fibrosis patients. During colonization of the lung, P. aeruginosa converts to a mucoid phenotype characterized by overproduction of the exopolysaccharide alginate. Here we show that AlgK, a protein essential for production of high molecular weight alginate, is an outer membrane lipoprotein that contributes to the correct localization of the porin AlgE. Our 2.5 A structure shows AlgK is composed of 9.5 tetratricopeptide-like repeats, and three putative sites of protein-protein interaction have been identified. Bioinformatics analysis suggests that BcsA, PgaA, and PelB, involved in the production and export of cellulose, poly-beta-1,6-N-Acetyl-D-glucosamine, and Pel exopolysaccharide, respectively, share the same topology as AlgK/E. Together, our data suggest that AlgK plays a role in the assembly of the alginate biosynthetic complex and represents the periplasmic component of a new type of outer membrane secretin that differs from canonical bacterial capsular polysaccharide secretion systems.
Related Citations: 
Expression, purification, crystallization and preliminary X-ray analysis of Pseudomonas fluorescens AlgK Keiski, C.-L., Yip, P., Robinson, H., Burrows, L.L., Howell, P.L. (2007) Acta Crystallogr Sect F Struct Biol Cryst Commun 63: 415
Organizational Affiliation: 
Molecular Structure and Function, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada.