The primary structure of sperm histone H1parecrJinus has been determined. H1par,c~Jinus consists of a polypeptide chain of the following 248 amino acid residues : Pro-Gly-Ser-Pro-Gln-Lys-Arg-Ala-AlaSer-Pro-Arg-Lys-Ser-Pro-Arg-Lys-Ser-Pro-Lys-Lys-Ser-Pro-Arg-Lys-Ala-Ser-Ala-Ser-Pro-Ala-Lys-Ala-Ala-Ala-Lys-Arg -Lys-Ala-Ala-Leu-Ala-LysLys-Lys -Ala-Ala-Ala-Ala-Lys-Arg-Lys-Ala-Ala -Ala-Lys -Ala-Lys -Lys-Ala-Lys-Lys -Pro -LysLys-Lys-Ala-Ala-Lys-Lys-Ala-Lys-Lys-Pro-Ala-Lys-Lys-Ser-Pro-Lys-Lys-Ala-Lys-Lys-ProAla-Lys-Lys-Ser-Pro-Lys-Lys-Lys-Lys-Ala-Lys-Arg-Ser-Pro-Lys-Lys-Ala-Lys-Lys-Ala-Ala-Ser-Pro-Lys-Lys-Ala-Arg-Lys. The protein consists of three domains. Compared to other HI and H5 histones, there is a very similar hydrophobic central domain and the carboxyl-terminal domain is very rich in lysine and alanine. Hlparectrcnus is similar to H5 histones in that the carboxyl-terminal domain also contains many arginine residues close to the carboxyl terminus. The carboxyl-terminal domain of HI P~~~~F~,~~ appears to have been constructed by a series of variable duplications. The amino-terminal domain of H~P~~~~J ,~~~~ is longer and quite different to that of other HI and H5 histones and is characterized by a repeating tetrapeptide of the general type Ser-Pro-(basic)z.The known sequence of a histone H1 gene from Psammechinus miliaris [Schaffner, W. et al. (1978) Cell, 14, 655-6711 is compared to the sequence of H1parecfJinus. Again the central hydrophobic domains are similar whereas the amino terminal domains are very different. Arg LysThe functions of the various domains of sperm histone H1parec~linus are discussed.In the preceding paper [l] the sequence of the first 84 residues of the sea urchin histone H1 have been reported. That investigation included a set of four cyanogen bromide fragments generated from the N-terminal region of the protein. The fifth CNBr peptide, CN-I, comprises 169 residues out of a total of 248 in the protein. The composition of CN-I is unusual insofar as 49 residues are alanine and 75 lysine and arginine. Such a composition indicates the presence of rather monotonous sequences, consisting possibly of an arrangement of reiterations of alanine lysine-rich stretches.Only few handles for breaking up this large cyanogen bromide fragment became evident from the composition of the fragment. The elucidation of the primary structure of this 169-residue fragment to be
SummaryThere are two glutamate dehydrogenases (GDH) produced by wild-type strains of N. cra88a, one of which is specific for the coenzyme NADP and the other for the coenzyme NAD. The latter enzyme (NAD-GDH) is induced if glutamate is used as the sole carbon and nitrogen source and is induced to a lesser extent if inorganic nitrogen is added. Addition of sucrose to the medium prevents uptake of glutamate and there is no induction of the enzyme.NADP-specific GDH activity is drastically decreased if glutamate is used as the sole carbon and nitrogen source. Addition of inorganic nitrogen causes a smaller decrease of NADP-GDH.If inorganic nitrogen is used as the sole nitrogen source together with sucrose as the carbon source, NADP-GDH activity is maintained for a longer period and NAD-GDH is not induced.
Mycelial pads of N. crassa grown for 48 hr in minimal medium were harvested, washed, and transferred to test media containing a variety of carbon and nitrogen sources. When some amino acids served as the sole carbon source, NAD-GDH was induced and the activity of NADP-GDH declined. Addition of sucrose depressed or prevented induction of NAD-GDH while NADP·GDH activity was maintained. Internal amino acid concentrations increased when mycelial pads were incubated in amino acids that induced NAD-GDH, but these accumulated amino acids were only oxidized in the absence of sucrose. The rate of amino acid accumulation decreased if sucrose was present in the media. A hypothesis is presented that the induction of NAD-GDH and the activity of NADP-GDH are a function of the ratio of amino acids to sucrose or sucrose metabolites or both. Urea was an excellent inducer of NAD-GDH in the presence or absence of sucrose, although the rate of induction was greater in the absence of sucrose. Incubation of mycelial pads in urea also led to extremely high concentrations of amino acids, thus supporting the ratio hypothesis. Mycelial pads incubated in media containing D-alanine accumulated the amino acid very efficiently, but metabolized it very poorly. Nevertheless, there was strong induction of NAD-GDH, indicating that amino acids per se were the compounds involved on one side of the balance. Addition of 58 mM sucrose to the test medium containing D·alanine prevented the induction of NAD-GDH but did not prevent the accumulation of alanine within the mycelium. Incubation of mycelial pads in media containing all combinations of 50 mM NH4Cl and 58 mM sucrose established that NH; enhanced the induction of NAD-GDH. NH; per se did not induce NAD-GDH.
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