A strong propensity toward loop formation characterizes the expressed reading frames of the D segments at the Ig H and T cell receptor loci

摘要

AbstractA compilation of murine and human Ig H and TcR β D segment sequences was used to estimate the relative usage of the various reading frames and to look for associated sequence patterns. We confirm a strong bias in the expression of the Ig H D segments, with more than 90 (murine) and 85 (human) expressed peptides resulting from a preferred reading frame. Remarkably, 86 (mouse) and 90 (human) of those peptides contain at least one glycine residue. All but one of the atypical preferred D peptides contain serine or proline residues and are found in the immediate vicinity of glycine residues provided by specific JHsegments. The presence of tyrosine residues is also a characteristic feature of expressed reading frames in both mouse (75) and human (90). These results suggest that the constraints of forming a flexible loop within the third complementarity‐determining region, is a factor in the preference for a particular reading frame in Ig H D. For the TcR β D segments, glycine is specified in most reading frames, and no significant preference is obser