Dependence of distance distributions derived from double electron-electron resonance pulsed EPR spectroscopy on pulse-sequence time.
Angew Chem Int Ed Engl
; 54(18): 5336-9, 2015 Apr 27.
Article
en En
| MEDLINE
| ID: mdl-25757985
ABSTRACT
Pulsed double electron-electron resonance (DEER) provides pairwise P(r) distance distributions in doubly spin labeled proteins. We report that in protonated proteins, P(r) is dependent on the length of the second echo period T owing to local environmental effects on the spin-label phase memory relaxation time Tm . For the protein ABD, this effect results in a 1.4â
Å increase in the P(r) maximum from T=6 to 20â
µs. Proteinâ
A has a bimodal P(r) distribution, and the relative height of the shorter distance peak at T=10â
µs, the shortest value required to obtain a reliable P(r), is reduced by 40 % relative to that found by extrapolation to T=0. Our results indicate that data at a series of Tâ
values are essential for quantitative interpretation of DEER to determine the extent of the T dependence and to extrapolate the results to T=0. Complete deuteration (99 %) of the protein was accompanied by a significant increase in Tm and effectively abolished the P(r) dependence on T.
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01-internacional
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MEDLINE
Asunto principal:
Proteínas
/
Espectroscopía de Resonancia por Spin del Electrón
/
Medición de Intercambio de Deuterio
Idioma:
En
Revista:
Angew Chem Int Ed Engl
Año:
2015
Tipo del documento:
Article