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Volumn 120, Issue 16, 1998, Pages 3823-3835

Characterization of a substrate-derived radical detected during the inactivation of ribonucleotide reductase from Escherichia coli by 2'- fluoromethylene-2'-deoxycytidine 5'-diphosphate

Author keywords

[No Author keywords available]

Indexed keywords

2' FLUOROMETHYLENE 2' DEOXYCYTIDINE 5' DIPHOSPHATE; ANTINEOPLASTIC AGENT; RIBONUCLEOTIDE REDUCTASE; TEZACITABINE; UNCLASSIFIED DRUG;

EID: 0032577017     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja972166e     Document Type: Article
Times cited : (48)

References (56)
  • 15
    • 2642613264 scopus 로고    scopus 로고
    • note
    • 2O. Incubation of this protein with (E)-1 and R2 generated an EPR spectrum identical to that shown in Figure 1C (data not shown). This result indicates that both hyperfine couplings in the radical are substrate-derived, consistent with Scheme 3.
  • 24
    • 2642710508 scopus 로고    scopus 로고
    • note
    • • species. Its spectral position is sensitive to the protonation (or hydrogen-bonding) state of the phenolic oxygen, while the width of the peak is determined by hyperfine splittings to ring ortho and β protons and, therefore, sensitive to rotational motion of the aromatic ring. Inspection of Figure 5A,B reveals that the predominant tyrosyl radical species contributing to the t = 30 s spectrum is a tyrosyl radical structurally very similar to the tyrosyl radical at t = 0 s, since this downfield peak has essentially the same spectral position and width. Thus, the spectral subtraction methodology employed here is valid within experimental uncertainty.
  • 26
    • 2642711331 scopus 로고    scopus 로고
    • note
    • 2
  • 34
    • 2642704657 scopus 로고    scopus 로고
    • note
    • In Scheme 5, the conjugate addition is arbitrarily drawn to occur from the α face (bottom face) of the enone. Addition from the β face would generate the epimers at C6′ of the structures in Scheme 5, but this would still lead to a 1:1 mixture of protonated and deuterated allyl radical species.
  • 35
    • 2642707955 scopus 로고    scopus 로고
    • note
    • 15 Thus, by process of elimination, formation of 18 (Scheme 6) would require that the thiyl radical at Cys439 adds to enone 4 from its β face.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.