Glutamate Mediates Proton-Coupled Electron Transfer Between Tyrosines 730 and 731 in Escherichia coli Ribonucleotide Reductase

Author(s):  
Clorice R. Reinhardt ◽  
Elvira R. Sayfutyarova ◽  
Jiayun Zhong ◽  
Sharon Hammes-Schiffer
2017 ◽  
Vol 61 (2) ◽  
pp. 281-292 ◽  
Author(s):  
Steven Y. Reece ◽  
Mohammad R. Seyedsayamdost

Escherichia coli class Ia ribonucleotide reductase (RNR) catalyzes the conversion of nucleotides to 2′-deoxynucleotides using a radical mechanism. Each turnover requires radical transfer from an assembled diferric tyrosyl radical (Y•) cofactor to the enzyme active site over 35 Å away. This unprecedented reaction occurs via an amino acid radical hopping pathway spanning two protein subunits. To study the mechanism of radical transport in RNR, a suite of biochemical approaches have been developed, such as site-directed incorporation of unnatural amino acids with altered electronic properties and photochemical generation of radical intermediates. The resulting variant RNRs have been investigated using a variety of time-resolved physical techniques, including transient absorption and stopped-flow UV-Vis spectroscopy, as well as rapid freeze-quench EPR, ENDOR, and PELDOR spectroscopic methods. The data suggest that radical transport occurs via proton-coupled electron transfer (PCET) and that the protein structure has evolved to manage the proton and electron transfer co-ordinates in order to prevent ‘off-pathway’ reactivity and build-up of oxidised intermediates. Thus, precise design and control over the factors that govern PCET is key to enabling reversible and long-range charge transport by amino acid radicals in RNR.


2013 ◽  
Vol 135 (23) ◽  
pp. 8585-8593 ◽  
Author(s):  
Bigna Wörsdörfer ◽  
Denise A. Conner ◽  
Kenichi Yokoyama ◽  
Jovan Livada ◽  
Mohammad Seyedsayamdost ◽  
...  

ChemInform ◽  
2003 ◽  
Vol 34 (32) ◽  
Author(s):  
JoAnne Stubbe ◽  
Daniel G. Nocera ◽  
Cyril S. Yee ◽  
Michelle C. Y. Chang

Biochemistry ◽  
1995 ◽  
Vol 34 (43) ◽  
pp. 14093-14103 ◽  
Author(s):  
Kathleen E. Silva ◽  
Timothy E. Elgren ◽  
Lawrence Que ◽  
Marian T. Stankovich

2013 ◽  
Vol 117 (28) ◽  
pp. 8457-8468 ◽  
Author(s):  
Adam R. Offenbacher ◽  
Lori A. Burns ◽  
C. David Sherrill ◽  
Bridgette A. Barry

1991 ◽  
Vol 266 (29) ◽  
pp. 19265-19268
Author(s):  
T.E. Elgren ◽  
J.B. Lynch ◽  
C. Juarez-Garcia ◽  
E. Münck ◽  
B.M. Sjöberg ◽  
...  

2019 ◽  
Vol 55 (63) ◽  
pp. 9399-9402 ◽  
Author(s):  
Tyler G. McCaslin ◽  
Cynthia V. Pagba ◽  
Hyea Hwang ◽  
James C. Gumbart ◽  
San-Hui Chi ◽  
...  

Tyrosine residues act as intermediates in proton coupled electron transfer reactions (PCET) in proteins.


Sign in / Sign up

Export Citation Format

Share Document