Structural studies on H-2Db and H-2Kd molecules indicate that murine major histocompatibility b and d haplotype alloantigens share structural features

Amino acid sequence analysis of the H-2Kk alloantigen: complete sequence of residues 1-98 and partial sequence from 99 to 263

The H-2Kk 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 NH2-terminal sequence for the H-2Kk molecule: [sequence in text]. 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-2Kk molecule; and (2) H-2Kk shares 79-83% homology in this region with other mouse class I molecules. Partial NH2-terminal amino acid sequences are also reported for the three disulfide-linked peptides. Several discrepancies from previously reported partial sequences of the H-2Kk molecule were detected.

A cDNA clone containing the entire coding sequence of a mouse H-2Kd histocompatibility antigen

We have isolated a cDNA clone carrying a 1560 bp long insert which contains the entire coding and 3' untranslated regions of an H-2K(d) mouse histocompatibility antigen. Its sequence and overal features are described. They point to the existence of unique properties of DNA sequences associated with the H-2K(d) antigen.

Disulfide structure of murine Ia alloantigens

The tryptic (T) and T insoluble chymotryptic (TIC) peptide maps from 35S-cysteine (Cys) labeled, disulfide-linked I-Ak dimer were compared to those from 35S-Cys labeled I-Ak alpha and beta chains which were not covalently linked. These comparisons indicated that the alpha and beta chains found in the covalent I-Ak dimer were not a specialized subset of I-A alpha and beta chains. Furthermore, these data, along with the knowledge that alkylation of spleen cells prior to and during detergent solubilization prevents the formation of disulfide-linked I-Ak dimer, indicate that covalent dimer formation is an inefficient and artifactual process. Comparison of the T and TIC peptide maps of reduced and nonreduced 35S-Cys labeled I-Ak alpha and beta chains suggests that the I-Ak alpha chain contains one intrachain disulfide bond, whereas the I-Ak beta chain contains two intrachain disulfide bonds. Examination of the T and TIC peptide maps of the reduced and nonreduced 35S-Cys labeled I-Ak dimer identifies the Cys-containing peptides which are involved in the formation of the artifactual I-Ak dimer interchain (alpha-beta) disulfide bond. Comparison of 35S-Cys labeled I-Ak and I-Ek alpha and beta chains by T and TIC peptide mapping reveals considerably more homology between the two alpha-chains and between the two beta-chains than is observed using other 3H-amino acid precursors, thus indicating that the I-Ak and I-Ek alloantigens are homologous in their amino acid sequences adjacent to the Cys resides. The reasons for the inability to induce formation of interchain (alpha-beta) disulfide bonds in I-Ek molecules are discussed.

Primary structure of the H-2Db alloantigen. II. Additional amino acid sequence information, localization of a third site of glycosylation and evidence for K and D region specific sequences

The complete amino acid sequence of the CNBr fragment comprising residues 229-284 of the murine major histocompatibility complex antigen H-2Db has been determined using radiochemical methodology. The sequence was determined by N-terminal sequence analysis of the intact CNBr fragment and by sequence determinations of peptides derived from this fragment by trypsin and staphylococcal V8 protease cleavage. In addition to the amino acid assignments for H-2Db, it was possible to assign the linkage position of the third N-linked glycosyl unit to the asparagine at residue 256. Additional amino acid sequence assignments have also been made for three other CNBr fragments that span residues 99-138, 139-228, and 308-331 of the H-2Db molecule. The total protein sequence information available (222 of 338 residues) agrees in every comparable position with the protein sequence derived from the cDNA clone (pH203) isolated by Reyes and co-workers (1982b), which strongly suggests that this clone encodes H-2Db. Combination of the protein sequence with that deduced from the cDNA clone provides the complete H-2Db protein sequence. Comparison of this sequence with other available protein sequence information for murine class I molecules has revealed protein sequences that may be unique to either K or D region molecules.

The complete amino acid sequence of the murine transplantation antigen H-2Db as deduced by molecular cloning

A mouse cDNA library derived from the EL4 cell line (b-haplotype) was screened with a probe containing a small part of the H-2Kb coding region. One of the clones isolated, pH203, encodes a protein whose deduced amino acid sequence is identical with the known sequence of H-2Db in 141 of 141 positions available for comparison. The clone, therefore, is believed to code for the H-2Db transplantation antigen. The cDNA insert of pH203 contains the coding region for residues 82 through the carboxy-terminus of H-2Db, and includes 476 nucleotides of the 3'-untranslated sequence. Comparison between the H-2Db cDNA clone and a previously isolated H-2Kb cDNA clone shows homologies of 83% and 91% at the amino acid and nucleotide levels, respectively. Analysis of DNA sequences at the 3'-coding and untranslated regions suggests that the mRNAs of H-2Kb and H-2Db are spliced differently at their 3'-coding ends.

cDNA clone coding for part of a mouse H-2d major histocompatibility antigen

mRNA coding for mouse major transplantation antigens of the d haplotype was partially purified, copied into double-stranded cDNA, and cloned in Escherichia coli. Clones were selected by their ability to hybridize specifically with mRNA coding for H-2K, D, or L antigens. One of these clones, pH-2d-1, carries a 1200-base-pair insert, comprising the noncoding region, including poly(A) at the 3' end and part of the coding region. A partial sequence of the latter region showed extensive homology with the known amino acid sequences of H-2Kb,Kk, and HLA-B7 antigens. From this comparison, it appears that the coding region extends from amino acid 133 in the second domain, through the third domain, to the cytoplasmic COOH-terminal region. A stretch of 24 hydrophobic or uncharged residues, located 31 amino acids from the COOH-terminal end, could represent the segment that spans the membrane. This is followed on the cytoplasmic side of the membrane by a cluster of basic amino acids and a possible phosphorylation site on a threonine residue.

Complete amino acid sequence of murine beta 2-microglobulin: structural evidence for strain-related polymorphism

Primary structural analyses of beta 3-microglobulin isolated from the tumor cell lines EL4.BU (derived from a C57BL/6 mouse) and C14 (derived from a BALB/c mouse) have revealed the presence of an amino acid difference at position 85 of this molecule. beta 2-Microglobulin isolated from histocompatibility antigens of EL4.BU has alanine at this position, whereas that from C14 has aspartic acid. Determination of the sequence of these molecules has employed radiochemical methodology that was developed in studies of murine histocompatibility antigens. The sequence obtained in this study is: Ile - Gln - Lys - Thr - Pro - Gln - Ile - Gln - Val - Tyr - Ser - Arg - His - Pro - Pro - Glu - Asn - Gly - Lys - Pro - Asn - Ile - Leu - Asn - Cys - Tyr - Val - Thr - Gln - Phe - His - Pro - Pro - His - Ile - Glu - Ile - Gln - Met - Leu - Lys - Asn - Gly - Lys - Lys - Ile Pro - Lys - Val - Glu - Met - Ser - Asp - Met - Ser - Phe - Ser - Lys - Asp - Trp - Ser - Phe - Tyr - Ile - Leu - Ala - His - Thr - Glu - Phe - Thr - Pro - Thr - Glu - Thr - Asp - Thr - Tyr - Ala - Cys - Arg - Val - Lys - His - Ala/Asp - Ser - Met - Ala - Glu - Pro - Lys - Thr - Val - Tyr - Trp - Asp - Arg - Asp - Met. Comparison of the sequence of murine beta 2-microglobulin to the sequences reported for the homologues from man, rabbit, and guinea pig indicate identities of 68%, 66%, and 61%, respectively.

Primary structure of murine major histocompatibility complex alloantigens: completion of the sequence of the amino-terminal 284 residues of H-2Kb

The primary structure of the COOH-terminal cyanogen bromide (CNBr) cleavage fragment Ic (CN-Ic) of the extracellular portion of the murine histocompatibility antigen H-2Kb has been completed. CN-Ic contains a site of papain cleavage which has been utilized for solubilizing H-2Kb by cleaving off the membrane integrating portion of the molecule. The amino acid sequence of CN-Ic has been determined by using peptides recovered after trypsin digestion of CN-Ic before and after blockage of lysine groups with citraconic anhydride. Overlapping sequences for the tryptic fragments were obtained by amino-terminal sequence analysis. The sequence of fragment CN-Ic, which spans residues 229-284 in H-2Kb, is as follows: Glu-Leu-Val-Glu-Thr-Arg-Pro-Ala-Gly-Asp-Gly-Thr-Phe-Gln-Lys-Trp-Ala-Ser-Val-Val-Pro-Leu-Gly-Lys-Glu-Gln-Tyr-Tyr-Thr-Cys-His-Val-Tyr-Gln-Gln-Gly-Leu-Pro-Gln-Pro-Leu-Thr-Leu-Arg-Trp-Asp-Glu-Pro-Pro-Ser-Thr-Val-Ser-Asn-Met. This amino acid sequence determination completes the primary structure of the amino terminal 284 residues of H-2Kb, that portion of this histocompatibility antigen which is external to the cell membrane and which contains antigenic determinants. It was also possible to identify Val-281 as a papain cleavage site within CN-Ic. The completed structure was analyzed solely by radiochemical methods. The structure obtained for H-2Kb is 71% homologous to the reported structure of HLA-B7, a human homologue.