Structural studies of the neural-cell-adhesion molecule by X-ray and neutron reflectivity

Colin P. Johnson, Giovanna Fragneto, Oleg Konovalov, Virginie Dubosclard, Jean Francois Legrand, Deborah E. Leckband

Research output: Contribution to journalArticlepeer-review


The structures of adhesion proteins play an important role in the formation of intercellular junctions and the control of intermembrane spacing. This paper describes the combination of neutron and X-ray specular reflectivity measurements to investigate the structure of the ectodomain of the neural-cell-adhesion molecule (NCAM). The measurements with unmodified NCAM suggest the presence of a bend in the extraceullar region. Measurements with the polysialic-acid-modified form of NCAM reveal that, at physiological ionic strength, the carbohydrate chains extend beyond the range of the unmodified protein. The excluded volume of the polymer is also ionic-strength-dependent, as expected for a polyelectrolyte. The structural characteristics obtained from these independent analyses of X-ray and neutron reflectivity data agree with each other, with prior reflectivity studies, and with molecular dimensions obtained from direct-force measurements. These results provide structural insights into the configuration of the NCAM ectodomain and the regulation of NCAM adhesion by post-translational modification.

Original languageEnglish (US)
Pages (from-to)546-554
Number of pages9
Issue number2
StatePublished - Jan 18 2005

ASJC Scopus subject areas

  • Biochemistry


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