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Query: UNIPROT:P06889 (Mol)
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In order to study the antigenic structure of histone H1(0) the purified protein from mouse liver was subjected to different chemical and enzymatic treatments (CNBr, acetic acid, trypsin, chymotrypsin). The resulting peptides were fractionated in SDS-containing or acid-urea polyacrylamide gels, transferred by electroblotting onto nitrocellulose paper and probed with specific rabbit anti-H1(0) antiserum. The C-terminal fragments 99-193 (obtained following acetic acid hydrolysis) and 107-193 (obtained by chymotrypsin digestion) also exhibited strong immunoreactivity. Fragment 1-30 (CNBr cleavage) contained antigenic determinants while the shorter fragments 1-22 and 1-28 (acetic acid hydrolysis) failed to show any detectable reactivity. It was concluded that, in contrast to histone H5 whose reactivity is mainly concentrated to the globular domain of the molecule, the antigenic determinants in histone H1(0) are more or less evenly distributed along the polypeptide chain with the possible exception of the short unstructured N-nose.
Mol Cell Biochem 1991 Oct 16
PMID:Antigenic structure of histone H1(0). 172 85

A structural homology is established between three DNA-binding phosphoproteins located in the 42 to 44 kDa range, referred to as pp42, pp43 and pp44, from Chironomus tentans salivary gland cells by in situ peptide mapping. The staining patterns of pp42, pp43 and pp44 which resulted from digestion with Staphylococcus aureus V8, trypsin or papain proteases show the presence of 8 to 15 spots majority of which have identical mobility. In the patterns of the digests generated by treatments with trypsin about 10 spots appear in common between any pair of the protein substrates. In addition, each pattern includes two to three peptides of mobility not present in the other. Thus the peptide mapping of pp42, pp43 and pp44 based on the staining patterns of proteolytic digests suggest the existence of structural homology between the three unlabelled substrates. The proteolytic peptides carrying the rapidly turning over phosphate groups form markedly different electrophoretic patterns than the unlabelled peptides visualized by staining. Treatment of 32P-labelled pp42, pp43 and pp44 with V8 generates only one labelled fragment in the 30 kD range. The cleavage patterns of pp44 produced by chymotrypsin or papain contain seven to ten labelled fragments while those of pp42 and pp43 contain only two. The 32P-labelled tryptic peptides of pp42, pp43 and pp44 exhibit a ladder pattern for each substrate which probably arise by a consecutive removal of 25 to 35 amino acid residues from the primary digestion products pp29, pp29.5 and pp30 by cleavage of four to five putative interdomain regions. The possibility that these three structurally related phosphoproteins belong to the category of transcription factors is discussed.
Mol Biol Rep 1991 May
PMID:Analysis of the structural relationships between the DNA-binding phosphoproteins pp42, pp43 and pp44 by in situ peptide mapping. 174 75

The binding of the recombinant proteinase inhibitor eglin c from the leech Hirudo medicinalis to serine (pro)enzymes belonging to the chymotrypsin and subtilisin families has been investigated from the thermodynamic viewpoint, between pH 4.5 and 9.5 and from 10 degrees C to 40 degrees C. The affinity of eglin c for the serine (pro)enzymes considered shows the following trend: Leu-proteinase [the leucine specific serine proteinase from spinach (Spinacia oleracea L.) leaves] greater than human leucocyte elastase congruent to human cathepsin G congruent to subtilisin Carlsberg congruent to bovine alpha-chymotrypsin greater than bovine alpha-chymotrypsinogen A congruent to porcine pancreatic elastase congruent to bovine beta-trypsin. The serine (pro)enzyme-inhibitor complex formation is an entropy-driven process. On increasing the pH from 4.5 to 9.5, the affinity of eglin c for the serine (pro)enzymes considered increases thus reflecting the acid pK shift of the invariant hystidyl catalytic residue from approximately to 6.9 in the free serine proteinases and bovine alpha-chymotrypsinogen A to congruent to 5.1 in the serine (pro)enzyme-inhibitor complexes. Considering the known molecular models, the observed binding behaviour of eglin c was related to the inferred stereochemistry of the serine (pro)enzyme-inhibitor contact regions.
J Mol Recognit
PMID:Binding of the recombinant proteinase inhibitor eglin c from leech Hirudo medicinalis to serine (pro)enzymes: a comparative thermodynamic study. 179 60

The myoglobin, cytochrome b5 and alpha-chymotrypsin hydrophobic nucleus sizes were calculated as well as sizes of theoretical spherical nucleus, radii that are equal to the lengths of phenylalanine and tryptophan lateral groups. All calculated values of sizes lie in the (0.99-1.65) nm3 interval. The quantitative estimation of analyzed proteins nucleus heterogeneous composition has been shown.
Mol Biol (Mosk)
PMID:[A comparative analysis of the structure of the myoglobin, cytochrome b5, and alpha-chymotrypsin hydrophobic nuclei]. 181 2

The amino acid sequences of peptides generated by trypsin and chymotrypsin digestions of the acidic PR4 chitinase from bean were determined. Oligonucleotide primers derived from this sequence were used to synthesize a PR4 chitinase-specific probe by PCR-amplification. This probe allowed the isolation of cDNA clones encoding PR4 chitinase that have been sequenced. This acidic and extracellular chitinase shows some homology to the basic isoform from the same plant, and differs from other known acidic chitinases by the presence of an amino-terminal cysteine-rich domain. Southern blot analysis of bean genomic DNA revealed that PR4 chitinase is encoded by a single gene.
Plant Mol Biol 1991 Aug
PMID:Isolation of a complementary DNA encoding the bean PR4 chitinase: an acidic enzyme with an amino-terminus cysteine-rich domain. 186 76

Variants of the human pancreatic secretory trypsin inhibitor (PSTI) have been created during a protein design project to generate a high-affinity inhibitor with respect to some serine proteases other than trypsin. Two modified versions of human PSTI with high affinity for chymotrypsin were crystallized as a complex with chymotrypsinogen. Both crystallize isomorphously in space group P4(1)2(1)2 with lattice constants a = 84.4 A, c = 86.7 A and diffract to 2.3 A resolution. The structure was solved by molecular replacement. The final R-value after refinement with 8.0 to 2.3 A resolution data was 19.5% for both complexes after inclusion of about 50 bound water molecules. The overall three-dimensional structure of PSTI is similar to the structure of porcine PSTI in the trypsinogen complex (1TGS). Small differences in the relative orientation of the binding loop and the core of the inhibitors indicate flexible adaptation to the proteases. The chymotrypsinogen part of the complex is similar to chymotrypsin. After refolding induced by binding of the inhibitor the root-mean-square difference of the active site residues A186 to A195 and A217 to A222 compared to chymotrypsin was 0.26 A.
J Mol Biol 1991 Aug 05
PMID:Three-dimensional structure of the complexes between bovine chymotrypsinogen A and two recombinant variants of human pancreatic secretory trypsin inhibitor (Kazal-type). 187 Jan 27

The egg jelly-induced acrosome reaction of the sea urchin, Strongylocentrotus intermedius, was inhibited by succinyl-Leu-Leu-Val-Tyr-4-methyl-coumaryl-7-amide (Suc-Leu-Leu-Val-Tyr-MCA), but not by Suc-Ala-Ala-Pro-Phe-MCA. The proteases with hydrolytic activity toward the former were purified from sperm extract by DEAE-Sephacel and hydroxylapatite chromatographies, Sephacryl S-300 gel filtration, and heparin-Sepharose CL-6B chromatography. Two types of protease were separated, and the molecular weights were estimated to be 65 and 700 kDa, respectively, by gel filtration. The former was accompanied by hydrolytic activity toward Suc-Ala-Ala-Pro-Phe-MCA, which was not hydrolyzed by the latter. Polyacrylamide gel electrophoresis of 700 kDa protease gave a single protein band under nondenaturing conditions and at least eight bands in the range of 22-33 kDa in the presence of sodium dodecyl sulfate (SDS). The substrate specificity and the inhibitor sensitivity of 700 kDa protease indicate that it contains two types of the activity, one is chymotrypsin-type and the other trypsin-type. The former activity was enhanced by poly-L-lysine or SDS. These properties of 700 kDa protease are similar to those of proteasomes (multicatalytic proteinases) isolated from various eukaryotic sources. We had previously shown that inhibitors of chymotrypsin-like proteases inhibit the increase of intracellular Ca2+ concentration by egg jelly, resulting in the inhibition of the acrosome reaction of St. intermedius (Matsumura and Aketa, Gamete Res 23:255-266, 1989). Bringing these findings together, we suggest that the chymotrypsin-like activity of sperm proteasome participates in the onset of the acrosome reaction of St. intermedius.
Mol Reprod Dev 1991 Jun
PMID:Proteasome (multicatalytic proteinase) of sea urchin sperm and its possible participation in the acrosome reaction. 187 26

The crystal structure of subtilisin BPN' complexed with a proteinaceous inhibitor SSI (Streptomyces subtilisin inhibitor) was refined at 1.8 A resolution to an R-factor of 0.177 with a root-mean-square deviation from ideal bond lengths of 0.014 A. The work finally established that the SSI-subtilisin complex is a Michaelis complex with a distance between the O gamma of active Ser221 and the carbonyl carbon of the scissile peptide bond being an intermediate value between a covalent bond and a van der Waals' contact, 2.7 A. This feature, as well as the geometry of the catalytic triad and the oxyanion hole, is coincident with that found in other highly refined crystal structures of the complex of subtilisin Novo, subtilisin Carlsberg, bovine trypsin or Streptomyces griseus protease B with their proteinaceous inhibitors. The enzyme-inhibitor beta-sheet interaction is composed of two separate parts: that between the P1-P3 residues of SSI and the 125-127 chain segment (the "S1-3 site") of subtilisin and that between the P4-P6 residues of SSI and th 102-104 chain segment (the "S4-6 site") of subtilisin. The latter beta-interaction is unique to subtilisin. In contrast, the beta-sheet interaction previously found in the complex of subtilisin Novo and chymotrypsin inhibitor 2 or in the complex of subtilisin Carlsberg and Eglin C is distinct from the present complex in that the two types of beta-interactions are not separate. As for the flexibility of the molecules comprising the present complex, the following observations were made by comparing the B-factors for free and complexed SSI and comparing those for free and complexed subtilisin BPN'. The rigidification of the component molecules upon complex formation occurs in a very localized region: in SSI, the "primary" and "secondary" contact regions and the flanking region; in subtilisin BPN', the S1-3 and S4-6 sites and the flanking region.
J Mol Biol 1991 Sep 05
PMID:Refined crystal structure of the complex of subtilisin BPN' and Streptomyces subtilisin inhibitor at 1.8 A resolution. 192 Apr 11

The conformation of estrogen receptor (ER) and its in vitro transformation by RNase, Urea and ATP were analysed using the uteri of young (16 weeks) and old (92 weeks) rats. Following the digestion of ER with proteolytic enzymes like trypsin and chymotrypsin and the analysis of cleaved fragments by SDS-PAGE, similar pattern is observed in both ages. In vitro transformation of ER by RNase, Urea and ATP shows that the degree of transformation is lower in old than young. Furthermore, the transformed ER from old is less capable of binding to DNA than that from young. Thus our results show that the conformation of ER probably does not change with age, but the degree of transformation and the ability of transformed receptor to bind to DNA decrease with age.
Mol Cell Biochem 1991 Jul 10
PMID:Analysis in vitro of uterine estrogen receptor conformation of young and old rats. 192 11

"Aged" organophosphoryl conjugates of serine hydrolases differ from the corresponding "non-aged" conjugates in their striking resistance to nucleophilic reactivation. The refined X-ray structures of "aged" and "non-aged" organophosphoryl conjugates of gamma-chymotrypsin were compared in order to understand the molecular basis for this resistance of "aged" conjugates. "Aged" and "non-aged" crystalline organophosphoryl-gamma-chymotrypsin conjugates were obtained by prolonged soaking of native gamma-chymotrypsin crystals with appropriate organophosphates. Thus, a representative "non-aged" conjugate, diethylphosphoryl-gamma-chymotrypsin, was obtained by soaking native crystals with paraoxon (diethyl-p-nitrophenyl phosphate), and a closely related "aged" conjugate, monoisopropyl-gamma-chymotrypsin, was obtained by soaking with diisopropylphosphorofluoridate. In both crystalline conjugates, the refined structures clearly reveal a high occupancy of the active site by the appropriate organophosphoryl moiety within covalent bonding distance of Ser195 O gamma. Whereas in the "non-aged" conjugate both ethyl groups can be visualized clearly, in the putative "aged" conjugate, as expected, only one isopropyl group is present. There is virtually no difference between the "aged" and "non-aged" conjugates either with respect to the conformation of the polypeptide backbone as a whole or with respect to the positioning of the side-chains within the active site. In the "aged" conjugate, however, close proximity (2.6 A) of the negatively charged phosphate oxygen atom of the dealkylated organophosphoryl group to His57 N epsilon 2 indicates the presence of a salt bridge between these two moieties. In contrast, in the "non-aged" conjugate the DEP moiety retains its two alkyl groups; thus, lacking a negative oxygen atom, it does not enter into such a charge-charge interaction and its nearest oxygen atom is 3.6 A away from His57 N epsilon 2. It is suggested that steric constraints imposed by the salt bridge in the "aged" conjugate lie at the basis of its resistance to reactivation.
J Mol Biol 1991 Oct 05
PMID:Refined crystal structures of "aged" and "non-aged" organophosphoryl conjugates of gamma-chymotrypsin. 194 36


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