生物物理学：触媒回転過程で放出される熱は酵素の拡散を促進する

Nature

517,

227–230

(08 January 2015)

doi:10.1038/nature14043

Received: 11 August 2014
Accepted: 05 November 2014
Published online: 10 December 2014
Corrected online: 07 January 2015

最近の研究で、酵素の拡散率は触媒反応中に基質依存的に増大することが示されている。この観察結果は複数の系で報告されていて、特徴も調べられているが、この現象が生じる仕組みは正確には分かっていない。熱量測定法は、酵素触媒反応からのエンタルピーを決定するのに用いられることが多く、そのために触媒反応の機構に関する重要な手掛かりが得られることがある。従来のバルク熱量測定に含まれるアンサンブル平均では、反応で交換されたエネルギーが触媒に及ぼす可能性のある一過性の影響を調べることができない。本論文では、単一分子蛍光相関分光法によるデータを得て、確率論的理論の枠組みを使って解析し、単一酵素分子の拡散促進と反応中に放出された熱の間の機構的関連を明らかにした。触媒反応中に放出された熱が、非対称的な圧力波を発生させ、それがタンパク質–溶媒の界面に差異的な応力をもたらし、一過的に酵素の質量中心を動かす（化学音響効果；chemoacoustic effect）と、我々は考えている。触媒反応中に放出されたエネルギーに酵素がどのように反応するのかという問題についてのこの新しい見方から、反応熱が酵素の構造的完全性や内部の自由度に与えると思われる影響が示唆される。

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Hope Adamson a, Alexandr N. Simonov b, Michelina Kierzek c, Richard A. Rothery c, Joel H. Weiner c, Alan M. Bond b, and Alison Parkin a,1 a Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom; b School of Chemistry, Monash University, Clayton, VIC 3800, Australia; and c Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada Edited by Harry B. Gray, California Institute of Technology, Pasadena, CA, and approved October 13, 2015 (received for review August 25, 2015) http://www.pnas.org/content/112/47/14506.short A long-standing contradiction in the field of mononuclear Mo enzyme research is that small-molecule chemistry on active-site mimic compounds predicts ligand participation in the electron transfer reactions, but biochemical measurements only suggest metal-centered catalytic electron transfer.With the simultaneous measurement of substrate turnover and reversible electron transfer that is provided by Fourier-...

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Tuning Reactivity and Selectivity in Hydrogen Atom Transfer from Aliphatic C–H Bonds to Alkoxyl Radicals: Role of Structural and Medium Effects

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C–H Bond Oxidation Catalyzed by an Imine-Based Iron Complex: A Mechanistic Insight

Giorgio Olivo§¶, Martina Nardi§, Diego Vìdal¶, Alessia Barbieri§, Andrea Lapi§‡, Laura Gómez¶⊥, Osvaldo Lanzalunga§‡, Miquel Costas*¶, and Stefano Di Stefano*§‡ § Università degli Studi di Roma, Rome, Italy ¶ Institut de Química Computacional i Catàlisi (IQCC), Girona, Spain Inorg. Chem., 2015, 54 (21), pp 10141–10152 DOI: 10.1021/acs.inorgchem.5b01500 Publication Date (Web): October 12, 2015 A family of imine-based nonheme iron(II) complexes (LX)2Fe(OTf)2 has been prepared, characterized, and employed as C–H oxidation catalysts. Ligands LX (X = 1, 2, 3, and 4) stand for tridentate imine ligands resulting from spontaneous condensation of 2-pycolyl-amine and 4-substituted-2-picolyl aldehydes. Fast and quantitative formation of the complex occurs just upon mixing aldehyde, amine, and Fe(OTf)2 in a 2:2:1 ratio in acetonitrile solution. The solid-state structures of (L1)2Fe(OTf)(ClO4) and (L3)2Fe(OTf)2 are reported, showing a low-spin octahedral iron center, with the lig...

Oxidative Alkene Cleavage Catalysed by Manganese-Dependent Cupin TM1459 from Thermotoga maritima

van Hajnal 1 , Kurt Faber 1,2 , Helmut Schwab 1,3 , Mélanie Hall 2,* and Kerstin Steiner 1,* a acib, Austrian Centre of Industrial Biotechnology GmbH, Petersgasse 14, 8010 Graz, Austria Fax: ( + 43)-316-873-9302; phone: ( + 43)-316-873-9346; e-mail: kerstin.steiner@acib.at b Department of Chemistry, University of Graz, Heinrichstraße 28, 8010 Graz, Austria Fax: ( + 43)-316-380-9840; phone: ( + 43)-316-380-5479; e-mail: melanie.hall@uni-graz.at c Institute of Molecular Biotechnology, TU Graz, Petersgasse 14, 8010 Graz, Austria Adv .S ynth. Catal. 2015 , 357 , 3 309 –3 316 DOI: 10.1002/adsc.201500608 Abstract A novel biocatalytic oxidative alkene cleavage activity was identified in protein TM1459 from Thermotoga maritima , a so far uncharacterised metalloprotein with a cupin fold, which preferentially binds manganese (over iron and zinc). Various styrene derivat...

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