title: The counterreceptor binding site of human CD2 exhibits an extended surface patch with multiple conformations fluctuating with millisecond to microsecond motions.
abstract: 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-microsecond) 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-microsecond). On the other hand, almost none of the residues of the CD58 binding side 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.
authors.affiliation: Procept Inc., Cambridge, Massachusetts 02139, USA.
authors.forename: D F
authors.initials: DF
authors.lastname: Wyss
authors.forename: K T
authors.initials: KT
authors.lastname: Dayie
authors.forename: G
authors.initials: G
authors.lastname: Wagner
mesh_terms: D001665:Binding Sites; D018801:CD2 Antigens / Q000378:metabolism*; D018360:Crystallography, X-Ray; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D011487:Protein Conformation; D011946:Receptors, Antigen / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature
chemical_list: D018801:CD2 Antigens; D011946:Receptors, Antigen