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Evidence by mutagen...
Evidence by mutagenesis that Tyr370 of the mouse ribonucleotide reductase R2 protein is the connecting link in the intersubunit radical transfer pathway
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Rova, Ulrika (författare)
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- Adrait, Annie (författare)
- Stockholms Universitet
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- Pötsch, Stephan (författare)
- Stockholms Universitet
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- Gräslund, Astrid (författare)
- Stockholms Universitet
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- Thelander, Lars (författare)
- Umeå universitet
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(creator_code:org_t)
- Elsevier BV, 1999
- 1999
- Engelska.
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Ingår i: Journal of Biological Chemistry. - : Elsevier BV. - 0021-9258 .- 1083-351X. ; 274:34, s. 23746-23751
- Relaterad länk:
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http://www.jbc.org/c...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Ribonucleotide reductase catalyzes all de novo synthesis of deoxyribonucleotides. The mammalian enzyme consists of two non-identical subunits, the R1 and R2 proteins, each inactive alone. The R1 subunit contains the active site, whereas the R2 protein harbors a binuclear iron center and a tyrosyl free radical essential for catalysis. It has been proposed that the radical properties of the R2 subunit are transferred ~35 Å to the active site of the R1 protein, through a coupled electron/proton transfer along a conserved hydrogen-bonded chain, i.e. a radical transfer pathway (RTP). To gain a better insight into the properties and requirements of the proposed RTP, we have used site-directed mutagenesis to replace the conserved tyrosine 370 in the mouse R2 protein with tryptophan or phenylalanine. This residue is located close to the flexible C terminus, known to be essential for binding to the R1 protein. Our results strongly indicate that Tyr370 links the RTP between the R1 and R2 proteins. Interruption of the hydrogen-bonded chain in Y370F inactivates the enzyme complex. Alteration of the same chain in Y370W slows down the RTP, resulting in a 58 times lower specific activity compared with the native R2 protein and a loss of the free radical during catalysis.
Ämnesord
- TEKNIK OCH TEKNOLOGIER -- Industriell bioteknik -- Bioprocessteknik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Industrial Biotechnology -- Bioprocess Technology (hsv//eng)
Nyckelord
- Biokemisk processteknik
- Biochemical Process Engineering
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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