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Title
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Spectral characterization of the recombinant mouse tumor suppressor 101F6 protein
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Author
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Abstract
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| Tumor suppressor protein 101F6, a gene product of the 3p21.3 (human) and 9F1 (mouse) chromosomal region, has recently been identified as a member of the cytochrome b561 (Cyt-b561) protein family by sequence homology. The His6-tagged recombinant mouse tumor suppressor Cyt-b561 protein (TSCytb) was recently expressed in yeast and purified, and the ascorbate reducibility was determined. TSCytb is auto-oxidizable and has two distinct heme b centers with redox potentials of ~40 and ~140 mV. Its split α-band in the dithionite-reduced spectrum at both 295 and 77 K is well resolved, and the separation between the two α-peaks is ~7 nm (~222 cm−1). Singular value decomposition analysis of the split α-band in the ascorbate-reduced spectra revealed the presence of two major spectral components, each of them with split α-band but with different peak separations (6 and 8 nm). Similar minor differences in peak separation were obtained when the split α-bands in ascorbate-reduced difference spectra at low (<1 mM) and high (>10 mM) ascorbate concentrations were analysed. According to low-temperature electron paramagnetic resonance (EPR) spectroscopy, the two heme b centers are in the low-spin ferric state with maximum principal g values of 3.61 and 2.96, respectively. These values differ from the ones observed for other members of the Cyt-b561 family. According to resonance Raman spectroscopy, the porphyrin rings are in a relaxed state. The spectroscopic results are only partially in agreement with those obtained earlier for the native chromaffin granule Cyt-b561. |
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Language
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English
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Source (journal)
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European biophysics journal. - Berlin
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Publication
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Berlin
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2010
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ISSN
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0175-7571
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DOI
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10.1007/S00249-009-0564-4
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Volume/pages
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39
:8
(2010)
, p. 1129-1142
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ISI
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000279194500003
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Full text (Publisher's DOI)
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