Histidine Biosynthesis

Miflin, B. J.

doi:10.1016/b978-0-12-675405-6.50020-6

Cited by 7 publications

(4 citation statements)

References 14 publications

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“…Because heat shock leads to more rapid depletion of the unlabeled histidine pool, and more rapid accumulation of single, double and triple-labeled histidine species, these results clearly indicate that heat shock increases the synthesis and turnover of histidine. Although we have not yet attempted to derive models to accommodate these labeling patterns, it is noteworthy that one of the nitrogen groups of histidine is thought to be derived from ATP and the other two from glutamate and glutamine-amide N (15). Assuming that glutamate and glutamine-amide would become more heavily '5N-labeled than ATP, the production of triple-labeled histidine species in the free pool should be largely dependent upon the rate of '5N labeling of the ATP pool.…”

Section: N Labeling Kinetics Of Intracellular Amino Acid Poolsmentioning

confidence: 99%

“…Temperature response curves for photosynthesis show a Qio of approximately 2 in the native desert species Tidestromia oblongifolia over the temperature range 15 to 40°C, but a Q,o of close to 0 over this same temperature range in the coastal species Atriplex glabriuscula, with extensive irreversible deactivation of photosynthesis at temperatures between 40°C and 50°C in the latter, but not the former species (2). Clearly, plant species exhibit striking variation for both the temperature optimum for photosynthesis and their genetically determined ability to acclimate to high temperatures (2).…”

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confidence: 99%

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Effects of Heat Shock on Amino Acid Metabolism of Cowpea Cells

Mayer

Cherry²,

Rhodes³

1990

Plant Physiol.

145

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When cowpea (Vigna unguiculata) cells maintained at 260C are transferred to 420C, rapid accumulation of y-aminobutyrate (>10-fold) is induced. Several other amino acids (including jB-alanine, alanine, and proline) are also accumulated, but less extensively than y-aminobutyrate. Total free amino acid levels are increased approximately 1.5-fold after 24 hours at 420C. Heat shock also leads to release of amino acids into the medium, indicating heat shock damage to the integrity of the plasmalemma. Some of the changes in metabolic rates associated with heat shock were estimated by monitoring the 15N labeling kinefics of free intracellular, extracellular and protein-bound amino acids of cultures supplied with 15NH4 , and analyzing the labeling data by computer simulation. Preliminary computer simulation models of nitrogen flux suggest that heat shock induces an increase in the yaminobutyrate synthesis rate from 12.5 nanomoles per hour per gram fresh weight in control cells maintained at 260C, to as high as 800 nanomoles per hour per gram fresh weight within the first 2 hours of heat shock. This 64-fold increase in the -y-aminobutyrate synthesis rate greatly exceeds the expected (Q10) change of metabolic rate of 2.5-to 3-fold due to a 160C increase in temperature. We suggest that this metabolic response may in part involve an activation of glutamate decarboxylase in vivo, perhaps mediated by a transient cytoplasmic acidification. Proline appears to be synthesized from glutamate and not from omithine in cowpea cells. Proline became severalfold more heavily labeled than omithine, citrulline and arginine in both control and heatshocked cultures. Proline synthesis rate was increased 2.7-fold by heat shock. Alanine, #B-alanine, valine, leucine, and isoleucine synthesis rates were increased 1.6-, 3.5-, 2.0-, 5.0-, and 6.0-fold, respectively, by heat shock. In contrast, the phenylalanine synthesis rate was decreased by 50% in response to heat shock.The differential effects of heat stress on metabolic rates lead to flux and pool size redistributions throughout the entire network of amino acid metabolism. where t, and t2 are the temperatures for velocities V, and V2 (21). For most enzyme-catalyzed reactions, Q,0 is between 1.5 and 2.5, and remains relatively constant over the physiological temperature range (0-50°C) (21). Thus, in general, rates of an enzyme reaction are expected to approximately double with every 10°C increase in temperature, assuming substrates in the reaction are nonlimiting, and assuming no irreversible thermal inactivation of the enzyme.Temperature response curves for photosynthesis show a Qio of approximately 2 in the native desert species Tidestromia oblongifolia over the temperature range 15 to 40°C, but a Q,o of close to 0 over this same temperature range in the coastal species Atriplex glabriuscula, with extensive irreversible deactivation of photosynthesis at temperatures between 40°C and 50°C in the latter, but not the former species (2). Clearly, plant species exhibit striking variation fo...

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Section: N Labeling Kinetics Of Intracellular Amino Acid Poolsmentioning

confidence: 99%

mentioning

confidence: 99%

Effects of Heat Shock on Amino Acid Metabolism of Cowpea Cells

Mayer

Cherry²,

Rhodes³

1990

Plant Physiol.

145

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“…Although histidine biosynthesis has been elucidated in several prokaryotic and eukaryotic microbes (18)(19)(20)(21)(22), the biosynthetic pathway in higher plants is unknown (23). Indirect evidence has indicated that the pathway follows a route similar to that found in bacteria and fungi (24,25).…”

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confidence: 99%

Structural and functional conservation of histidinol dehydrogenase between plants and microbes.

Nagai

Ward

Beck

et al. 1991

Proc. Natl. Acad. Sci. U.S.A.

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The partial amino acid sequence of histidinol dehydrogenase (L-histidinol:NAD+ oxidoreductase, EC 1.1.1.23) from cabbage was determined from peptide fragments of the purified protein. The relative positions of these peptides were deduced by aligning their sequences with the sequence of the HIS4C gene product of Saccharomyces cerevisiae. cDNA encoding histidinol dehydrogenase was then amplified from a library using a polymerase chain reaction primed with degenerate oligonucleotide pools of known position and orientation. By using this amplified fragment as a probe, an apparently fulD-length cDNA clone was isolated that is predicted to encode a proenzyme having a putative 31-amino acid chloroplast transit peptide and a mature molecular mass of47.5 kDa. The predicted protein sequence was 51% identical to the yeast enzyme and 49% identical to the Escherichia coli enzyme. Expression of the cDNA clone in an E. coli his operon deletion strain rendered the mutant able to grow in the presence of histidinol.In plants, the biosynthetic pathways of most of the amino acids are poorly understood. Only a handful of enzymes involved in amino acid biosynthesis have been purified from plant sources, partly because of the small amount of these proteins found in plant cells. To date, glutamate synthase, glutamate dehydrogenase, and glutamine synthetase in the glutamate pathway (1-3), aspartate kinase (4) and homoserine dehydrogenase (5) in the threonine pathway, dihydrodipicolinate synthase (6) in the lysine pathway, and 3-deoxy-D-arabinoheptulosonate 7-phosphate synthase (7) and 5-enoylpyruvyl shikimate-3-phosphate synthase (8) in the aromatic amino acid pathway have been characterized and purified from various plant species. cDNAs encoding several of these enzymes have been cloned (8-12), as have genes for other amino acid biosynthetic enzymes based on their structural or functional homology to microbial or mammalian enzymes (13-17).Although histidine biosynthesis has been elucidated in several prokaryotic and eukaryotic microbes (18-22), the biosynthetic pathway in higher plants is unknown (23). Indirect evidence has indicated that the pathway follows a route similar to that found in bacteria and fungi (24,25). Recently, histidinol dehydrogenase (HDH; L-histidinol:NAD+ oxidoreductase, EC 1.1.1.23) was purified to homogeneity from Brassica oleracea (cabbage; ref. 26), proving that the final steps in histidine biosynthesis proceed in plants as they do in prokaryotes and fungi.In this report, we describe the isolation ofa full-length cDNA encoding HDH from cabbage. The plant coding sequence ¶ was approximately 50o identical to known microbial genes. To demonstrate function of the plant clone, the cDNA was expressed in an Escherichia coli strain lacking the histidine operon. The cDNA was found to suppress the his deletion when the bacteria were grown in the presence of histidinol. MATERIALS AND METHODSPlant Material and Bacterial Strains. Mature spring cabbage (Brassica oleracea L. var capitata L.) was purchased from a local...

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“…IGPD is involved in the His biosynthetic pathway in both microorganisms and higher plants (Wiater et al, 1971b;Miflin, 1980;Mano et al, 1993) and catalyzes a dehydration reaction to produce IAP from IGP (Ames and Mitchell, 1955;Ames, 1957). Thus, we designed triazole compounds to inhibit the enzyme reaction by considering the structure of IGP and its possible isosteres, and their enzyme inhibi- tion potencies were enhanced through a systematic study of the structure-activity relationship.…”

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confidence: 99%

A Novel Class of Herbicides (Specific Inhibitors of Imidazoleglycerol Phosphate Dehydratase)

Mori¹,

Fonne-Pfister²,

Matsunaga³

et al. 1995

Plant Physiol.

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A new mode of herbicidal action was established by finding specific inhibitors of imidazoleglycerol phosphate dehydratase, an enzyme of histidine (His) biosynthesis. Three triazole phosphonates inhibited the reaction of the enzyme with Ki values of 40 f 6.5, 10 f 1.6, and 8.5 2 1.4 nM, respectively, and were highly cytotoxic to cultured plant cells. This effect was completely reversed by the addition of His, proving that the cytotoxicity was primarily caused by the inhibition of His biosynthesis. These inhibitors showed widespectrum, postemergent herbicidal activity at application rates ranging from 0.05 to 2 kg/ha.

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Histidine Biosynthesis

Cited by 7 publications

References 14 publications

Effects of Heat Shock on Amino Acid Metabolism of Cowpea Cells

Effects of Heat Shock on Amino Acid Metabolism of Cowpea Cells

Structural and functional conservation of histidinol dehydrogenase between plants and microbes.

A Novel Class of Herbicides (Specific Inhibitors of Imidazoleglycerol Phosphate Dehydratase)

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