Amino acid sequence analysis of the H-2K k alloantigen: Complete sequence of residues 1–98 and partial sequence from 99 to 263

Abstract

The H-2K k molecule was purified by immunoprecipitation from the glycoprotein fraction of Nonidet P-40 extracts of RDM 4 mouse tumor cells. Cyanogen bromide cleavage of the major papain fragment yielded three peptides, the largest of which consisted of three disulfide-linked peptides which could be separated after reduction and alkylation. These peptides were readily aligned by their homology to similar fragments derived from other H-2 class I molecules. Amino acid sequence analyses of the two nondisulfide-linked peptides, peptide E (residues 1–52) and peptide D (53–98), yielded the following NH 2-terminal sequence for the H-2K k molecule: G-P-H-S-L-R-Y-F-H-T-A-V-S-R-P-G-L-G-K-P-R-F-I- S-V-G-Y-V-D-D-T-Q-F-V-R-F-D-S-D-A-E-N-P-R-Y-E-P-R-(A)-R-(W)-(M)-E-Q-V-E-P-E-Y-W-E-R- N-T-Q-I-A-K-G-N-E-Q-I-F-R-V-N-L-R-T-A-L-R-Y-Y-(N)-Q-S-A-G-G-S-H-T-F-Q-R-(M). Comparison of this sequence with those of other H-2 class I molecules revealed that: (1) Lys-19, Val-55, Glu-56, Asn-63 and Ile-73 are unique to the H-2K k molecule; and (2) H-2K k shares 79–83% homology in this region with other mouse class I molecules. Partial NH 2-terminal amino acid sequences are also reported for the three disulfide-linked peptides. Several discrepancies from previously reported partial sequences of the H-2K k molecule were detected.