Anion-mediated Fe3+ Release Mechanism in Ovotransferrin C-lobe
IR@CSIR-CFTRI
View Archive InfoField | Value | |
Relation |
http://ir.cftri.com/1624/
JBC-12-01 |
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Title |
Anion-mediated Fe3+ Release Mechanism in Ovotransferrin C-lobe
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Creator |
Kimihiko, Mizutani
Muralidhara, B. K. Honami, Yamashita Satoshi, Tabata |
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Subject |
29 Protein Chemistry
03 Proteins |
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Description |
The differential properties of anion-mediated Fe3_ release between the N- and C-lobes of transferrins have been a focus in transferrin biochemistry. The structural and kinetic characteristics for isolated lobe have, however,been documented with the N-lobe only. Here we demonstrate for the first time the quantitative Fe3_ release kinetics and the anion-binding structure for the isolated C-lobe of ovotransferrin. In the presence of pyrophosphate, sulfate, and nitrilotriacetate anions, the C-lobe released Fe3_ with a decelerated rate in a single exponential progress curve, and the observed first order rate constants displayed a hyperbolic profile as a function of the anion concentration. The profile was consistent with a newly derived single-pathway Fe3_ release model in which the holo form is converted depending on the anion concentration into a “mixed ligand” intermediate that releases Fe3_. The apo C-lobe was crystallized in ammonium sulfate solution, and the structure determined at 2.3 Å resolution demonstrated the existence of a single bound SO4 2_ in the interdomain cleft, which interacts directly with Thr461-OG1, Tyr431-OH, and His592-NE2 and indirectly with Tyr524-OH. The latter three groups are Fe3_-coordinating ligands, strongly suggesting the facilitated Fe3_ release upon the anion occupation at this site. The SO4 2_ binding structure supported the single-pathway kinetic model. |
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Date |
2001-09
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Type |
Article
PeerReviewed |
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Format |
application/pdf
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Language |
en
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Rights |
—
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Identifier |
http://ir.cftri.com/1624/1/JBC_276_35940_-_35946_2001_NA.pdf
Kimihiko, Mizutani and Muralidhara, B. K. and Honami, Yamashita and Satoshi, Tabata (2001) Anion-mediated Fe3+ Release Mechanism in Ovotransferrin C-lobe. Journal of Biological Chemistry, 276 (28). pp. 35940-35946. |
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