STUDIES ON BIOSYNTHETIC ENZYMES: I. MUTANT FORMS OF HISTIDINOL DEHYDROGENASE FROM NEUROSPORA CRASSA

1965 ◽  
Vol 43 (7) ◽  
pp. 993-1000 ◽  
Author(s):  
E. H. Creaser ◽  
D. J. Bennett ◽  
R. B. Drysdale
Keyword(s):  
Activation Energy ◽  
Neurospora Crassa ◽  
Kinetic Properties ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Temperature Sensitive Mutants ◽  
Michaelis Constants ◽  
Histidinol Dehydrogenase ◽  
Mutant Forms ◽  
Two Temperature

Data are presented on the kinetic properties of the enzyme histidinol dehydrogenase obtained from the wild type Neurospora crassa and from 15 mutants. Differences were observed in pH curves and in Michaelis constants, both for histidinol and NAD. Ten mutants had modified affinity for NAD and three for histidinol, and one was modified in both these parameters. Two temperature-sensitive mutants were found to have an enzyme with a different activation energy from the normal. The data are discussed in relation to theories about whether histidinol dehydrogenase is a multifunctional enzyme in this organism or is part of an operon system.

scholarly journals Amino acid substitutions in mutant forms of histidinol dehydrogenase from Neurospora crassa

1967 ◽  
Vol 105 (1) ◽  
pp. 39-44 ◽  
Author(s):  
D J Bennett ◽  
E H Creaser
Keyword(s):  
Amino Acid ◽  
Neurospora Crassa ◽  
Temperature Sensitive ◽  
Amino Acid Substitutions ◽  
Wild Type ◽  
Temperature Sensitive Mutants ◽  
Nad Oxidoreductase ◽  
Histidinol Dehydrogenase ◽  
Mutant Forms ◽  
Two Temperature

Amino acid changes in the enzyme l-histidinol dehydrogenase (l-histidinol–NAD oxidoreductase, EC 1.1.1.23) have been determined between the wild-type Neurospora crassa and two temperature-sensitive mutants. Comparison was made between amino acid analyses of peptides of differing electrophoretic and chromatographic mobilities resulting from tryptic and chymotryptic digestion of protein from wild-type and mutant K26, and wild-type and mutant K445 strains, respectively. The analyses demonstrate the substitution of aspartic acid for alanine in mutant K26, and leucine for histidine in mutant K445. The effects of the resulting changes in polarity and charge are discussed in relation to the catalytic functioning of the proteins.

scholarly journals Role of SpoVA Proteins in Release of Dipicolinic Acid during Germination of Bacillus subtilis Spores Triggered by Dodecylamine or Lysozyme

2006 ◽  
Vol 189 (5) ◽  
pp. 1565-1572 ◽  
Author(s):  
Venkata Ramana Vepachedu ◽  
Peter Setlow
Keyword(s):  
Bacillus Subtilis ◽  
Small Molecules ◽  
Spore Germination ◽  
Dipicolinic Acid ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Ph Optimum ◽  
Inner Membrane ◽  
Temperature Sensitive Mutants

ABSTRACT The release of dipicolinic acid (DPA) during the germination of Bacillus subtilis spores by the cationic surfactant dodecylamine exhibited a pH optimum of ∼9 and a temperature optimum of 60°C. DPA release during dodecylamine germination of B. subtilis spores with fourfold-elevated levels of the SpoVA proteins that have been suggested to be involved in the release of DPA during nutrient germination was about fourfold faster than DPA release during dodecylamine germination of wild-type spores and was inhibited by HgCl2. Spores carrying temperature-sensitive mutants in the spoVA operon were also temperature sensitive in DPA release during dodecylamine germination as well as in lysozyme germination of decoated spores. In addition to DPA, dodecylamine triggered the release of amounts of Ca2+ almost equivalent to those of DPA, and at least one other abundant spore small molecule, glutamic acid, was released in parallel with Ca2+ and DPA. These data indicate that (i) dodecylamine triggers spore germination by opening a channel in the inner membrane for Ca2+-DPA and other small molecules, (ii) this channel is composed at least in part of proteins, and (iii) SpoVA proteins are involved in the release of Ca2+-DPA and other small molecules during spore germination, perhaps by being a part of a channel in the spore's inner membrane.

scholarly journals AN ENRICHMENT FOR TEMPERATURE-SENSITIVE MUTANTS IN TETRAHYMENA THERMOPHILA

Genetics ◽  
1979 ◽  
Vol 92 (4) ◽  
pp. 1079-1092
Author(s):  
Duane W Martindale ◽  
Ronald E Pearlman
Keyword(s):  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Wild Type ◽  
Macromolecular Synthesis ◽  
Treatment Results ◽  
Uv Treatment ◽  
Temperature Sensitive Mutants ◽  
Near Ultraviolet ◽  
Treatment Data ◽  
Resistant Mutants

ABSTRACT The parameters for the killing of Tetrahymena by 5-bromodeoxyuridine (BUdR) and near-ultraviolet light have been determined. Significant preferential killing by UV* of cells that have incorporated BUdR was obtained when the cells were irradiated in a nonnutrient buffer. UV alone was found to be toxic to cells irradiated in growth medium. Mutants defective in division at a restrictive temperature were isolated from mutagenized cultures that had been treated with BUdR and UV and from mutagenized cultures that had no such treatment. Results indicate that the number of temperature sensitive (ts) growth mutants can be increased five to six times using the BUdR/UV treatment. Data are presented that indicate differences in the frequency of occurrence of various types of ts mutants, with and without enrichment. A mutant that immediately stopped macromolecular synthesis and cell division upon being placed at the restrictive temperature was more resistant to BUdR/UV treatment than wild type by 1000-fold. Using the above techniques, BUdR-resistant mutants altered in the phosphorylation of thymidine have been isolated.

Identification of the defects in the hemagglutinin gene of two temperature-sensitive mutants of A/WSN/33 influenza virus

Virology ◽  
1986 ◽  
Vol 154 (2) ◽  
pp. 279-285 ◽  
Author(s):  
Setsuko Nakajima ◽  
Donald J. Brown ◽  
Masahiro Ueda ◽  
Katsuhisa Nakajima ◽  
Akira Sugiura ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Temperature Sensitive ◽  
Temperature Sensitive Mutants ◽  
Hemagglutinin Gene ◽  
Two Temperature
Sign in / Sign up

Export Citation Format

Share Document