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→Biosynthesis: Added a brief paragraph (3 sentences) on a gene in the fungus N. crassa that encodes 3 of the enzyme activities of the histidine biosynthetic pathway. |
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Histidine is synthesized from [[phosphoribosyl pyrophosphate]] (PRPP), which is made from [[ribose-5-phosphate]] by [[ribose-phosphate diphosphokinase]] in the [[pentose phosphate pathway]]. The first reaction of histidine biosynthesis is the condensation of PRPP and [[adenosine triphosphate]] (ATP) by the enzyme [[ATP phosphoribosyltransferase|ATP-phosphoribosyl transferase]]. ATP-phosphoribosyl transferase is indicated by His1 in the image.<ref name=":1" /> His4 gene product then hydrolyzes the product of the condensation, phosphoribosyl-ATP, producing phosphoribosyl-AMP (PRAMP), which is an irreversible step. His4 then catalyzes the formation of phosphoribosylformiminoAICAR-phosphate, which is then converted to phosphoribulosylformimino-AICAR-P by the His6 gene product.<ref name=":2">{{Cite journal|last1=Kulis-Horn|first1=Robert K|last2=Persicke|first2=Marcus|last3=Kalinowski|first3=Jörn|date=2014-01-01|title=Histidine biosynthesis, its regulation and biotechnological application in Corynebacterium glutamicum|journal=Microbial Biotechnology|volume=7|issue=1|pages=5–25|doi=10.1111/1751-7915.12055|issn=1751-7915|pmc=3896937|pmid=23617600}}</ref> His7 splits phosphoribulosylformimino-AICAR-P to form {{sm|d}}-erythro-imidazole-glycerol-phosphate. After, His3 forms imidazole acetol-phosphate releasing water. His5 then makes {{sm|l}}-histidinol-phosphate, which is then hydrolyzed by His2 making [[histidinol]]. [[Histidinol dehydrogenase|His4]] catalyzes the oxidation of {{sm|l}}-histidinol to form {{sm|l}}-histidinal, an amino aldehyde. In the last step, {{sm|l}}-histidinal is converted to {{sm|l}}-histidine.<ref name=":2" /><ref>{{Cite journal|last=Adams|first=E.|date=1955-11-01|title=L-Histidinal, a biosynthetic precursor of histidine|journal=The Journal of Biological Chemistry|volume=217|issue=1|pages=325–344|doi=10.1016/S0021-9258(19)57184-8|issn=0021-9258|pmid=13271397|doi-access=free}}</ref>
The histidine biosynthesis pathway has been studied in the fungus ''[[Neurospora crassa]]'', and a gene (''His-3'') encoding a [[multienzyme complex]] was found that was similar to the ''His4'' gene of the bacterium ''[[Escherichia coli|E. coli]]''.<ref name = Ahmed1968>Ahmed A. Organization of the histidine-3 region of Neurospora. Mol Gen Genet. 1968;103(2):185-93. doi: 10.1007/BF00427145. PMID: 4306011</ref>
Just like animals and microorganisms, plants need histidine for their growth and development.<ref name=":0" /> Microorganisms and plants are similar in that they can synthesize histidine.<ref>{{Cite web|url=http://genetics.thetech.org/ask/ask396|title=Understanding Genetics|website=genetics.thetech.org|access-date=2016-05-19}}</ref> Both synthesize histidine from the biochemical intermediate phosphoribosyl pyrophosphate. In general, the histidine biosynthesis is very similar in plants and microorganisms.<ref>{{Cite journal|last1=Stepansky|first1=A.|last2=Leustek|first2=T.|date=2006-03-01|title=Histidine biosynthesis in plants|journal=Amino Acids|volume=30|issue=2|pages=127–142|doi=10.1007/s00726-005-0247-0|issn=0939-4451|pmid=16547652|s2cid=23733445}}</ref>
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== External links ==
*[http://gmd.mpimp-golm.mpg.de/Spectrums/a4fc4f0c-0812-4f61-94fd-a79c61419670.aspx Histidine MS Spectrum]
{{Amino acids}}
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