Comparative Peptide Mapping Research Articles

Structural Studies on the Murine Ia Alloantigens

Abstract The α and β subunits of the murine I-A alloantigens from several H-2 haplotypes were examined by comparative tryptic peptide mapping by using double label (3H and 14C) techniques. Significant structural variation between alleles was detected in both subunits. Tryptic digests of the α polypeptides from s, b, and d showed only 65% co-elution with k; β-chains from s, b, d, and r were about 50% similar to the k β subunit. Peptide analysis of the Ak subunits from intra-H-2 recombinant strains indicated that both the α and β polypeptides are encoded within the I-A subregion.

Partial N-terminal amino acid sequence analyses and comparative tryptic peptide maps of murine Ia molecules encoded by the I-A subregion.

The partial N-terminal amino acid sequences and tryptic peptide maps of I-A subregion products from the H-2b, H-2d, H-2k and H-2s haplotypes demonstrate that haplotype-associated differences are present in both alpha and beta polypeptides. The genetic and evolutionary implications of these multiple amino acid substitutions and the homology relationships among Ia molecules from human, guinea pig and the I-E subregion of the mouse are discussed.

Purified desmin from adult mammalian skeletal muscle: A peptide mapping comparison with desmins from adult mammalian and avian smooth muscle

Comparative one-dimensional peptide maps were prepared by the electrophoresis of digests derived from treatment of desmins with Ca 2+-activated muscle protease, trypsin, Staphylococcus aureus V8 protease, and cyanogen bromide. Desmins from adult mammalian skeletal and smooth muscles were very similar. Avian smooth muscle desmin, although homologous with respect to many peptides, was different from the mammalian smooth and skeletal desmins. The amino acid compositions of the three desmins were quite similar.

In vitro synthesis, glycosylation, and membrane insertion of influenza virus haemagglutinin

The synthesis of influenza virus haemagglutinin (HA) has been studied, using cell-free systems primed with cellular RNA from chick embryo fibroblast (CEF) cells infected with influenza virus (A/Japan/305/57-Bellamy/42(H 2N 1)). In L-cell and wheat germ cell-free systems, a precursor to the HA protein of apparent molecular weight 63,000 was identified by immunoprecipitation and by comparative peptide mapping of this product and the 75,000-dalton glycopolypeptide HA precursor synthesised during infection of CEF cells. The 63,000-dalton precursor was converted to a product of apparent molecular weight 75,000 by addition of dog pancreas membrane vesicles during in vitro translation. The 75,000-dalton protein made in the presence of membranes is protected from trypsin digestion and binds to lectin-Sepharose. These, and further results, suggest that HA is extruded into membrane vesicles and glycosylated during synthesis.

Structural studies on the murine Ia alloantigens. V. Evidence that the structural gene for the I-E/C beta polypeptide is encoded within the I-A subregion.

The E/C alpha- and beta-subunits of intra-I-region recombinants were analyzed for primary structural variation by comparative tryptic peptide mapping. The E/C alpha-polypeptides from B10.A, B10.A (3R) and B10.A (5R) showed complete coincident elution of peptides; the E/C beta-chains from B10.A and 3R (or 5R) were approximately 40% different. This suggests that the structural gene for the E/C beta-polypeptide is within the I-A subregion.

Isolation and partial characterization of secreted mouse pituitary prolactin

Prolactin secreted by mouse anterior pituitaries was purified by gel filtration on Sephadex G-100. Electrophoretic homogeneity of the purified hormone was demonstrated in several gel systems, and electrophoresis in the presence of sodium dodecyl sulfate indicated an apparent molecular weight of 21 000 ± 2000. Mouse and ovine prolactin displayed parallel dose vs. response curves in radioreceptor binding studies, indicating that these two hormones compete for identical receptor sites on rabbit mammary membranes. Comparative peptide mapping studies carried out on tryptic digests of mouse and ovine prolactin suggested only partial homology between the two hormones. Internally labeled monomeric mouse prolactin was observed to undergo aggregation following storage at −20°C for 2 months.

Comparative peptide mapping of baculovirus polyhedrins

Amino terminals and two-dimensional high-voltage peptide maps of tryptic digests of polyhedrins from Heliothis armigera nuclear polyhedrosis virus (NPV), Heliothis zea NPV, and Anticarsa gemmatalis NPV were compared with previously characterized granulins and polyhedrins. Similarities and differences were detected in the tryptic maps, while each protein produced a unique peptide map composite. Amino-terminal determination of eight polyhedrins and granulins resulted in three different end groups.

Secretion granules of the rabbit parotid. Selective removal of secretory contaminants from granule membranes.

A membrane subfraction obtained from secretion granules isolated from rabbit parotid has been shown to be contaminated by residual secretory proteins to an estimated level of 25-30% of its total protein. In the present study an additional contaminant has been identified by improved mixing experiments and by comparative peptide mapping of specific polypeptides recovered from gels of membrane and content subfractions. This contaminant coelectrophoresis with (and probably comprises the bulk of) the majority component of the membrane subfraction (mol wt approximately 40,000). The contaminating polypeptides can be removed to a large extent by treating the membranes with low concentrations of saponin in the presence of 0.3 M Na2SO4. Although this treatment disrupts the typical bilayer structure of the granule membrane, it does not appear to cause dissociation of its phospholipids or bona fide membrane proteins.

Comparative peptide mapping of radioiodinated light chains derived from homogeneous rabbit anti-streptococcal antibodies

Comparative peptide mapping of radioiodinated light chains derived from homogeneous rabbit anti-streptococcal antibodies

On the relationship of brain filaments to microtubules.

Abstract— A method has been developed for the isolation of a previously undescribed fibrous protein from rat brain. The newly isolated material consists of bundles of tightly packed 70‐80 Å diameter filaments. Based on studies employing degenerated rat optic nerve, it is proposed that these filaments correspond to the well‐described astrocyte filaments observed in sectioned preparations of mammalian brain. The purified filaments are stable over a wide temperature range, are not disrupted by colchicine, and exhibit limited solubility in the absence of denaturants or detergents. In neutral SDS‐polyacrylamide gel electrophoresis, the filament protein runs as a single band with an apparent molecular weight of 57,000 daltons. This preparation also migrates as a single band in alkaline urea gels, and as a well‐resolved doublet on discontinuous SDS‐urea gels. In all three electrophoretic systems, the filament subunits co‐migrate with rat brain tubulin. Comparative peptide maps of the filament subunits and tubulin indicate a large degree of homology. Our results suggest that microtubules and astrocyte filaments are composed of the same or very similar protein subunits.

Studies on Fd-fragments of human immunoglobulins: I. A comparative peptide mapping study on l-chains, Fab- and Fd-fragments of G-myeloma proteins

The Fab-fragments and corresponding L-chains of four G(1)-Gm(f+) myeloma proteins were studied by comparative peptide mapping. Of the 15–20 peptides found to be derived from the Fd-fragment, 7 were considered to be common in regard to position and staining to the Fd-fragments of the myeloma globulins studied. The total number of Fd-peptides found in the composites was too low, as judged from the amino acid analysis and from sequence data from the literature. This was due to an overlap of tryptic peptides from Fd-fragments and L-chains. The Fd-fragment of one monoclonal protein could be isolated and studied by peptide mapping. The number of Fd-peptides thus found (25–28) was in good agreement with the expected number from the amino acid analysis. The homologous peptides of Fd and corresponding L-chains could be traced in the peptide maps. In connection with this aspect the relevance of finding “common” peptides is discussed. The Gm(f+) peptide (free arginine) could be localized in the Fd-maps.

Two Antigenic Subtypes of Human Lambda Immunoglobulin Chains

Summary Two subtypes St(+) and St(-) of human lambda polypeptide chains were distinguished by immunochemical tests. Five of 27 Bence Jones proteins contained antigenic determinants that were not detected in the other 22 proteins. The distinctive antigenic sites were demonstrated with a heterologous rabbit antiserum produced to a lambda Bence Jones protein. The St(+) lambda chain subtype is present in light chains from pooled normal human immunoglobulin G. The results of comparative tryptic peptide mapping suggest that the specific St(+) determinants are localized on the variable (N-terminal) half of the lambda chains. St(+) lambda chains have been found to be Oz(-) (arginine residue at position 190 of the C-terminal half of the chain). Twenty-three per cent of the St(-) proteins were Oz(+) (lysine residue at position 190) and 77% of the St(-) proteins were Oz(-).