Combined pseudo-merohedral twinning, non-crystallographic symmetry and pseudo-translation in a monoclinic crystal form of the gammadelta T-cell ligand T10

Acta Crystallogr D Biol Crystallogr. 2004 Apr;60(Pt 4):656-64. doi: 10.1107/S0907444904002239. Epub 2004 Mar 23.


T10 is a non-classical class Ib-like major histocompatibility complex (MHC) cell-surface antigen which binds directly to certain gammadelta T-cell receptors in the absence of any exogenous and endogenous ligands, such as peculiar lipids or glycolipids. The crystal structure at 2.5 A resolution of murine T10 was determined by molecular replacement using data from an almost perfectly twinned monoclinic crystal. The space group is P2(1), with unit-cell parameters a = 78.2, b = 70.0, c = 139.2 A, beta = 106.8 degrees. Self-rotation function analysis and various intensity statistics revealed the presence of pseudo-merohedral twinning, but these tests underestimated the true twin fraction of alpha approximately 0.46. Native Patterson analyses pointed to the presence of pseudo-translation among the four molecules present in the asymmetric unit. Data analysis, structure determination and model refinement are discussed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antigens, Surface / chemistry*
  • Antigens, Surface / immunology
  • Crystallization
  • Crystallography, X-Ray
  • H-2 Antigens / chemistry*
  • Mice
  • Models, Molecular
  • Molecular Structure
  • Protein Conformation
  • Receptors, Antigen, T-Cell, gamma-delta / immunology


  • Antigens, Surface
  • H-2 Antigens
  • Receptors, Antigen, T-Cell, gamma-delta
  • T10 antigen, mouse