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Crystal Structure Analysis of the Repair of Iron Centers Protein YtfE and Its Interaction with NO
Author(s) -
Lo FengChun,
Hsieh ChangChih,
MaestreReyna Manuel,
Chen ChinYu,
Ko TzuPing,
Horng YihChern,
Lai YeiChen,
Chiang YunWei,
Chou ChihMao,
Chiang ChengHung,
Huang WeiNing,
Lin YiHung,
Bohle D. Scott,
Liaw WenFeng
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201600990
Subject(s) - chemistry , electron paramagnetic resonance , crystallography , nitrosylation , reactivity (psychology) , crystal structure , magnetic circular dichroism , stereochemistry , nitric oxide , nuclear magnetic resonance , physics , medicine , alternative medicine , organic chemistry , pathology , astronomy , spectral line
Molecular mechanisms underlying the repair of nitrosylated [Fe–S] clusters by the microbial protein YtfE remain poorly understood. The X‐ray crystal structure of YtfE, in combination with EPR, magnetic circular dichroism (MCD), UV, and 17 O‐labeling electron spin echo envelope modulation measurements, show that each iron of the oxo‐bridged Fe II –Fe III diiron core is coordinatively unsaturated with each iron bound to two bridging carboxylates and two terminal histidines in addition to an oxo‐bridge. Structural analysis reveals that there are two solvent‐accessible tunnels, both of which converge to the diiron center and are critical for capturing substrates. The reactivity of the reduced‐form Fe II –Fe II YtfE toward nitric oxide demonstrates that the prerequisite for N 2 O production requires the two iron sites to be nitrosylated simultaneously. Specifically, the nitrosylation of the two iron sites prior to their reductive coupling to produce N 2 O is cooperative. This result suggests that, in addition to any repair of iron centers (RIC) activity, YtfE acts as an NO‐trapping scavenger to promote the NO to N 2 O transformation under low NO flux, which precedes nitrosative stress.