The counterreceptor binding site of human CD2 exhibits an extended surface patch with multiple conformations fluctuating with millisecond to microsecond motions

• Published in: Protein science Vol. 6; no. 3; pp. 534 - 542
• Main Authors: Wyss, Daniel F., Dayie, Kwaku T., Wagner, Gerhard
• Format: Journal Article
• Language: English
• Published: Bristol Cold Spring Harbor Laboratory Press 01.03.1997
• Subjects: 15N NMR relaxation; Binding Sites; CD2 Antigens - metabolism; Crystallography, X-Ray; glycosylated human CD2 adhesion domain; Humans; immunoglobulin superfamily V‐set domain; Magnetic Resonance Spectroscopy; Protein Conformation; Receptors, Antigen - chemistry; Receptors, Antigen - metabolism; reduced spectral density mapping; Temperature
• ISSN: 0961-8368; 1469-896X
• DOI: 10.1002/pro.5560060303

We have used 15N NMR relaxation experiments to probe, for the glycosylated human CD2 adhesion domain, the overall molecular motion, as well as very fast nanosecond‐picosecond (ns‐ps) and slow millisecond‐microsecond (ms‐/xs) internal motions. Using a novel analysis method that considers all residues, we obtained a correlation time for the overall motion of 9.5 ± 0.3 ns. Surprisingly, we found a large contiguous patch of residues in the counterreceptor (CD58) binding site of human CD2 exhibiting slow conformational exchange motions (ms‐ytis). On the other hand, almost none of the residues of the CD58 binding site display fast (ns‐ps) internal motions of amplitudes larger than what is seen for well‐ordered regions of the structure. Residues close to the N‐glycosylation site, and the first N‐acetylglucosamine of the high mannose glycan are as rigid as the protein core. Residues conserved in the immunoglobulin superfamily V‐set domain are generally very rigid.