ISSN:
1572-8773
Keywords:
capsule secondary structure
;
exopolysaccharide
;
bacterial cell surface
;
copper
;
mercury
;
ytterbium
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract Escherichia coli K1 secretes a homopolymer capsular polysaccharide (CPS) consisting of alpha 2,8 linked N-acetylneuraminic acid (poly α2,8NeuNAc). Typically poly α2,8NeuNAc is arranged in low and high order alpha helices with carboxyl and hydroxyl groups extending from the helices. Several properties of CPS such as antigenicity and metal binding can be influenced by its structural conformation. We examined the influences of metal ions and temperature on the secondary structure of polyαa2,8NeuNAc. Conformation alteration was detected by ultraviolet (UV) spectroscopy and circular dichroism (CD). The majority of metal ions tested had no detectable influence on poly a2,8NeuNAc structure. In contrast, Yb3+., Hg2+, and Cu2+ ions greatly altered the UV and CD spectra, which suggests that these ions had disrupted the alpha helical structure of poly α2,8NeuNAc. These changes were influenced by the metal ion concentration. When poly α2,8NeuNAc was incubated at temperatures ranging from 20 - 60°C, alterations in its UV absorption spectra were also seen. The most significant change occurred between 35 and 40°C. In summary, this study suggests that the higher order structure and function of bacterial CPS may be influenced by environmental factors
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009294829309
