Histidinol dehydrogenase from Neurospora crass

Creaser, E. H.

Drysdale, R. B.

Fungal Genetics Reports

English

Kansas State University

Fungal Genetics Reports Volume 3 Article 1 Histidinol dehydrogenase from Neurospora crassa E. H. Creaser R. B. Drysdale Follow this and additional works at: https://newprairiepress.org/fgr This work is licensed under a Creative Commons Attribution-Share Alike 4.0 License. Recommended Citation Creaser, E. H., and R.B. Drysdale (1963) "Histidinol dehydrogenase from Neurospora crassa," Fungal Genetics Reports: Vol. 3, Article 1. https://doi.org/10.4148/1941-4765.2139 This Research Note is brought to you for free and open access by New Prairie Press. It has been accepted for inclusion in Fungal Genetics Reports by an authorized administrator of New Prairie Press. For more information, please contact cads@k-state.edu. Histidinol dehydrogenase from Neurospora crassa Abstract Histidinol dehydrogenase from Neurospora crassa This research note is available in Fungal Genetics Reports: https://newprairiepress.org/fgr/vol3/iss1/1 RESEARCH NOTES Creaser, E.H. and R. B. Drysdale. Histidinol --__ dehydrogenase from Neurosooro w. It is thought that the locus histidine-3 controls hvo functions in Neurospora, the first of these being in the early stages ot histidine biosynthesis and largely unknown at present. The second function is to direct the formation of the terminal enzyme in the sequence- histidinol dehydrogenase. We have studied the purification and some properties of this enzyme. The enzyme con be extracted from wet mycelium by grinding with gloss powder or from dried mycelium by extraction with pH 9. I Tris buffer. The extract is treated with 0.05M MnC12 to prec:pitate nucleic acids and unwonted proteins. Ammonium sulphate is added to 50% saturation and the precipitate discorded. The saturation is increased to 65% and the precipitate which contains the enzyme is retained. The enzyme is quite heat stable and con be further purified by heat treatment and chromatography on DEAE cellulose. The product accounts for approximately 0. I% of the protein of Neurosporo. The enzyme is specific for NAD, its optimum pH is in excess of IO, it is Mgtt activated and aged preparations con be reactivated by thio- glycollic acid or cysteine. Normal and sucrose densify gradient ultrocentrifugotion indicates o molecular weight of 36,000 to 40,000, The enzyme from heterocaryons and o Iso from histidine-3 mutants which lock the first function con be purified by the some procedures.---Department of Microbiology, University of Birmingham, Birmingham, England. de Serres, F. J. and B. B. Webber. Recessive Genetic analyses of recessive lethal mutations lethal mutations resulting from deletion of induced in o heterokaryon suggest that the majority closely linked loci in balanced heterokaryons of of X ray-induced ad-3 mutations ore the result of Neurospora crosso. deletions involving ad-3A or ad-3E locus or both (de Serves and Osterbind, Genet’n 793, 1962, and unpublished data). Th e presence of closely linked biochemical markers in the adenineqequiring com- ponent of the dikaryon used in these experiments ond the use of medium supplemented only with adenine prevented the recovery of genetic alterations extending into the nearby hist-2 lotus or nit-2 locus. In theory, ad-3 mutations resulting from large deletions involving loci in a-t regions should be re- coverable by appropriate supplementation of the incubation medium. The ability to recover and maintain such intergenic alterations in o balanced heterokaryon moy be inferred from the experiments of Atwood ond Mukai (Proc. Notl. Acad. Sci., U.S. 39: 1027, 1953). In their tests, those recessive lethal mutations participating in “inclusive complexes” were assumed to represent chromosome deficiencies of indeterminate size. The present experiments show that some recessive lethal mutations result from events that simultaneously inactivate o series of linked loci. These are most simply interpreted os genetic deletions. The strain numbers and genetic markers in each component of the dikoryon used ore given in Table I. With this heterokaryon one should expect to recover os a purple colony in adenine- and niacin-supplemented medium almost any intergenic alteration on the right arm of linkage group I in component B which in- activates at least one of the ad-3 loci. Linkage group Component A (74-OR60-29A) Component B (74-OR31-16A) IR hi+2 ad-3A ad-3B nit-2 ---- Ill ad-2 IV V inos VI --r al-2 cot - pan-2 

Histidinol dehydrogenase from Neurospora crassa

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