Molecular recognition of antigenic polysaccharides: a conformational comparison of capsules from Streptococcus pneumoniae serogroup 9.
Aqueous solution conformations of three antigenic bacterial capsular polysaccharides (CPS) from S. pneumoniae serogroup 9 were determined using a combination of NMR data (NOE build-up rates and conformation-dependent chemical shifts), simulated annealing, and molecular dynamics simulations. Each polymer adopts a flexible extended ribbon conformation in solution. Conformations of structural elements shared by each PS are indistinguishable. Differences in conformations are minor and localised at the sites of structural variations; there is no evidence of long-range stabilisation of a secondary structure. It is likely that antigenic specificity of Group 9 PS is dominated by local structural variation rather than by conformational differences.
Laboratory for Molecular Structure, National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, United Kingdom.
T J
TJ
Rutherford
C
C
Jones
D B
DB
Davies
A C
AC
Elliott
D016667:Bacterial Capsules / Q000737:chemistry*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D013296:Streptococcus pneumoniae / Q000737:chemistry*