Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0009443 (cold)
 92,137 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hemoglobin (Hb) Tarrant was detected by its electrophoretic mobility on cellulose acetate (pH 8.4) and citrate agar (pH 6.2). On cellulose acetate it moved as a band between hemoglobins F and S, and on citrate agar as a band at hemoglobin S. The test for solubility in 2 M phosphate buffer with Na2S2O4 was negative. The new variant has a substitution of asparagine for aspartic acid in position 126 of the alpha-chain, one of the sites involved in the alpha1beta1 contact. Furthermore, in deoxyhemoglobin aspartic acid 126 of each alpha chain also forms a non-covalent electrostatic salt bridge with arginine 141 of the corresponding alpha chain (Perutz, M. F. and Ten Eyck, L. F. (1972) Cold Spring Harbor Symp. Quant. Biol. 36, 295-310 and Perutz, M. F. (1970) Nature 228, 726-739). As a consequence of this substitution in hemoglobin Tarrant, the deoxy conformation or T state is destabilized because these two bridges cannot be formed. This condition is reflected in high oxygen affinity and low cooperativity.
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PMID:Hemoglobin Tarrant: alpha126(H9) Asp leads to Asn. A new hemoglobin variant in the alpha1beta1 contact region showing high oxygen affinity and reduced cooperativity. 1 56

Information compiled by automatic Edman degradation of Streptomyces griseus trypsin coupled with previous data has permitted the assignment of the first 36 residues at the NH2 terminus of the protein. Cyanogen bromide cleavage at the three methionine residues followed or preceded by reduction and aminoethylation resulted in the production of four fragments, Cnl to Cn4, which were separated by gel filtration on Sephadex G-50 or G-75. Fragments CN4 (15 RESIDUES) AND Cn3 (5 residues) were shown to be derived from the NH2 terminus of the protein while Cn2 (47 residues and devoid of homoserine) was from the COOH terminus. The arrangement of the fragments was thus Cn4-Cn3-Cn1-Cn2. Automatic Edman degradation in the sequenator coupled with peptides derived from alpha-lytic protease and chymotryptic digestion and from the peptic and tryptic peptides previously elucidated have permitted the sequence determination of fragments Cn1 and Cn2 and therefore of the whole protein. These studies show that extensive regions of identity or similarity exist between Streptomyces griseus trypsin and bovine trypsin. These include the NH2-terminal four residues, the sequences near histidine-57 (chymotrypsinogen A numbering system), aspartic acid-102, aspartic acid-189, and serine-195, the regions of the three disulfide bridges, and the COOH-terminal end (residues 225-229) of the proteins. When aligned to maximize homology the identity of residues is 34%. This identity is increased to 54% when only those residues classified as internal by Stroud et al. (Stroud, R. M., Kay, L. M., and Dickerson, R. E. (1971) Cold Spring Harbor Symp. Quant. Biol. 36, 125) are considered. These results indicate that the folding of the polypeptide chains of the two enzymes is very similar and are in agreement with the very similar enzymic, chemical, and physical properties of the two enzymes.
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PMID:Amino acid sequence of Streptomyces griseus trypsin. Cyanogen bromide fragments and complete sequence. 80 14

Cold agglutinins are human autoantibodies, usually of the IgM class, which agglutinate RBC at low temperature. The major subset recognizes the I/i carbohydrate Ag, and many of these antibodies bear cross-reacting idiotypic determinants. An anti-idiotypic mAb that is specific for one of the idiotopes largely confined to cold agglutinins has been used to identify and monitor tumor cells that secrete these molecules in two patients. The tumor cells were immortalized with EBV and the idiotope-positive lines used to investigate the utilization of the VH and VL genes by these antibodies. Nucleotide sequence analysis of the two cold agglutinins (FS-1 and FS-2) revealed the utilization of a single common gene segment, VH4-21. Serologic analysis documented that only human antibodies utilizing the VH4-21 gene segment were reactive in the idiotope assay, other VHIV antibodies as well as a panel of antibodies derived from other VH families being negative. The DH, JH, VK, and JK gene segments of FS-1 and FS-2 were structurally distinct. These data suggest that the structural basis for the cross-reactive idiotope as well as cold agglutinin activity is the VH4-21 gene segment. A nucleotide change in H chain CDR1 of both cold agglutinins results in the substitution of an aspartic acid residue for glycine at position 31, suggesting that this amino acid might be critical to recognition of the red cell Ag.
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PMID:Nucleotide sequence analysis of the V regions of two IgM cold agglutinins. Evidence that the VH4-21 gene segment is responsible for the major cross-reactive idiotype. 171 Feb 50

The two stereoisomers of pyroglutamic acid (PCA), a nootropic or cognition-enhancing agent, and classic reference compounds were investigated for their ability to interact with 27 neurotransmitter receptors and drug binding sites prepared from selected areas of the central nervous system and labelled with high affinity and selectivity with specific radioligands. L-PCA significantly interacted with the rat forebrain excitatory amino acid receptors labelled with 3H-L-glutamic acid. The IC50 of L-PCA was 28.11 microM, that of cold L-glutamic acid was 1.68 microM. The corresponding figure for L-aspartic acid was 16.95 microM. The indirect Hill plot gave coefficients of 0.48, 1.08 and 0.75 for L-PCA, L-glutamic and L-aspartic acids, respectively. Only very high concentrations (10(-4) M) of L-PCA were able to slightly antagonize the specific binding of 3H-clonidine to alpha 2-adrenergic receptors, of 3H-dihydroalprenolol to beta 1- and beta 2-adrenergic receptors of the heart and of the lung and of 3H-diazepam to benzodiazepine receptors. The D-isomer of PCA was practically as active as the L-isomer on these receptors. Finally, L-PCA (10(-5) to 10(-4) M) was unable to antagonize the specific binding of all the other radioligands to their respective receptors and binding sites. D-PCA did not significantly interact with excitatory amino acid receptors or with any of the other sites studied here.
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PMID:Investigations on the binding properties of the nootropic agent pyroglutamic acid. 197 55

Nephrocalcin is a urinary glycopeptide that may be a physiological inhibitor of nephrolithiasis. Monomeric nephrocalcin purified from ethylenediaminetetracetic acid-treated urine is 14,000 daltons. Compositional analyses indicate that nephrocalcin is 10 per cent carbohydrate by weight and that 25 per cent of the amino acid residues are acidic (glutamic acid, aspartic acid and gamma-carboxyglutamic acid). Nephrocalcin binds reversibly to calcium oxalate crystals with a dissociation constant of about 0.5 microM. The high collapse pressure of nephrocalcin, 41.5 dynes per cm., measured for a monolayer at the air-water interface, suggests a highly organized structure in which hydrophilic and hydrophobic regions occupy separate regions on the surface of the inhibitor. Nephrocalcin contains the unusual amino acid, gamma-carboxyglutamic acid. Nephrocalcin isolated from urine of stone formers and from kidney stones does not contain gamma-carboxyglutamic acid and it has altered surface properties compared to normal nephrocalcin. The presence of the gamma-carboxyglutamic acid modification and the ability to form stable films with high collapse pressures may be important factors enabling nephrocalcin to prevent stone formation in vivo. The blood of cold water fishes contains antifreeze glycopeptides and/or peptides to prevent it from freezing. The structure of one such antifreeze peptide and its interactions with the crystal lattice of hexagonal ice are discussed as a model for how nephrocalcin might interact with calcium oxalate crystals and arrest their growth in urine.
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PMID:Protein inhibitors of crystal growth. 264 34

The effect of hypoxia, cold and hypoxic-cold stress was studied on plasma and brain amino acid levels of rats. Hypoxia caused a considerable increase in plasma taurine and phosphoserine levels, while the remaining amino acids (except valine, cystine, iso-leucine, leucine and anserine) decreased significantly. On the other hand cold stress significantly increased the plasma taurine, asparagine and decreased glutamine, glycine, alanine, methionine and histidine levels. The hypoxic-cold stress combination produced marked decrease in most of the plasma levels of amino acids (except phosphoserine, taurine and anserine). During brain amino acid studies, hypoxia significantly elevated taurine, aspartic acid, valine and leucine levels while the concentrations of other amino acids were not significantly altered. Cold stress was found to elevate taurine and valine levels, while leucine and phenyl-alanine levels were significantly decreased. Exposure of animals to hypoxic-hypothermia affected significantly the brain levels of valine, methionine, leucine and arginine. Since, the change in amino acid levels in brain is less prominent, as compared with plasma, in response to stress, it appeared that brain possesses higher adaptive mechanisms to counteract the stress induced amino acid level imbalance.
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PMID:Effect of hypoxia and/or cold stress on plasma and brain amino acids in rat. 274 Jun 20

The cold agglutinin isolated from the albumin gland of the snail Achatina fulica was modified with various chemical reagents in order to detect the amino acids and/or carbohydrate residues present in its carbohydrate-binding sites. Treatment with reagents considered specific for modification of lysine, arginine and tryptophan residues of the cold agglutinin did not affect the carbohydrate-binding activity of the agglutinin. Modification of tyrosine residues showed some change. However, modification with carbodiimide followed by alpha-aminobutyric acid methyl ester causes almost complete loss of its binding activity, indicating the involvement of aspartic acid and glutamic acid in its carbohydrate-binding activity. The carbohydrate residues of the cold agglutinin were removed by beta-elimination reaction, indicating that the sugars are O-glycosidically linked to protein part of the molecule. Removal of galactose residues from the cold agglutinin by the action of beta-galactosidase indicated that the galactose molecules are beta-linked. These carbohydrate-modified glycoproteins showed a marked change in agglutination property, i.e. they agglutinated rabbit erythrocytes at both 10 degrees C and 25 degrees C, indicating that the galactose residues of the glycoprotein play an important role in the cold-agglutination property of the glycoprotein. The c.d. data showed the presence of an almost identical type of random-coil conformation in the native cold agglutinin at 10 degrees C and in the carbohydrate-modified glycoprotein at 10 degrees C and 25 degrees C. This particular random-coil conformation is essential for carbohydrate-binding property of the agglutinin.
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PMID:Studies on chemical modification of cold agglutinin from the snail Achatina fulica. 311 67

The cold agglutinin from the albumin gland of the snail Achatina fulica was purified to homogeneity by using sheep gastric mucin-Sepharose 4B as affinity column followed by gel filtration on Bio-Gel P-300. The homogeneity was checked by alkaline gel electrophoresis, immunodiffusion and immunoelectrophoresis. The purified cold agglutinin is a glycoprotein of native M2 220,000 consisting of three non-covalently bound subunits of Mr 84,000, 74,000 and 62,000 and having a pI value of 4.5. The predominant amino acids are aspartic acid and glutamic acid (or amides) and serine, which account for 39% of the residues. About 3% of the residues are half-cystine. The lectin is a glycoprotein with about 30.7% carbohydrate, the most abundant sugars being galactose, N-acetylgalactosamine and N-acetylglucosamine. Mannose, xylose and fucose are also present. The inhibition of agglutination of human umbilical-cord erythrocytes by the cold agglutinin is specific for methyl beta-D-galactoside and also for glycolipids present on cord erythrocytes. The c.d. data show only negative ellipticity values in the far-u.v. region for the protein at various concentrations and temperatures and also in the presence of the hapten lactose (at different concentrations), indicating the presence of a random-coil conformation in the agglutinin that varies according to temperature.
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PMID:Further characterization of the cold agglutinin from the snail Achatina fulica. 359 52

We have identified the amino acid substitutions in two mutant forms of the recA protein from Escherichia coli. The recA441 mutant, which shows constitutive expression of the recA-mediated SOS response at 42 degrees C, contains two amino acid substitutions, glutamic acid to lysine at residue 38 and isoleucine to valine at residue 298. The recA629 mutant is an unusual pseudorevertant of recA441 that is no longer capable of spontaneous expression of SOS functions at 42 degrees C. Purified recA629 protein is cold-labile for several of the wild-type enzymatic activities and is shown here to contain three amino acid substitutions, the two found in the recA441 protein at residues 38 and 298, as well as an aspartic acid-to-glycine change at residue 32. The mutation at residue 32 was verified by restriction digestion of the 5' region of the recA629 structural gene.
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PMID:Identification of the amino acid substitutions in two mutant forms of the recA protein from Escherichia coli: recA441 and recA629. 608 37

The polyoma virus (Py) transformed cell line 7axB, selected by in vivo passage of an in vitro transformed cell, contains an integrated tandem array of 2.4 genomes and produces the large, middle, and small Py T-antigen species, with molecular weights of 100,000, 55,000, and 22,000, respectively (Hayday et al., J. Virol. 44:67-77, 1982; Lania et al., Cold Spring Harbor Symp. Quant. Biol. 44:597-603, 1980). The integrated viral and adjacent host DNA sequences have been molecularly cloned as three EcoRI fragments (Hayday et al.). One of these fragments (7B-M), derived from within the tandem viral sequences, is equivalent to an EcoRI viral linear molecule. Fragment 7B-M has been found to be transformation competent but incapable of producing infectious virus after DNA transfection (Hayday et al.). By constructing chimerae between 7B-M and Py DNA and by direct DNA sequencing, the mutation responsible for the loss of infectivity has been located to a single base change (adenine to guanine) at nucleotide 2503. This results in a conversion of an aspartic acid to a glycine in the C-terminal region of the Py large T-antigen but does not appear to affect the binding of the Py large T-antigen to Py DNA at the putative DNA replication and autoregulation binding sites. The mutation is located within a 21-amino acid homology region shared by the simian virus 40 large T-antigen (Friedmann et al., Cell 17:715-724, 1979). These results suggest that the mutation in the 7axB large T-antigen may be involved in the active site of the protein for DNA replication.
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PMID:Loss of polyoma virus infectivity as a result of a single amino acid change in a region of polyoma virus large T-antigen which has extensive amino acid homology with simian virus 40 large T-antigen. 630 Apr 29


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