Article Metrics


Online attention

Structural and biochemical investigation of class I ribonucleotide reductase from the hyperthermophile Aquifex aeolicus

DOI: 10.1021/acs.biochem.1c00503 DOI Help

Authors: Daniel Rehling (Stockholm University) , Emma Rose Scaletti (Stockholm University) , Inna Rozman Grinberg (Stockholm University) , Daniel Lundin (Stockholm University) , Margareta Sahlin (Stockholm University) , Anders Hofer (Umeå University) , Britt-Marie Sjöberg (Stockholm University) , Pal Stenmark (Stockholm University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Biochemistry

State: Published (Approved)
Published: December 2021

Open Access Open Access

Abstract: Ribonucleotide reductase (RNR) is an essential enzyme with a complex mechanism of allosteric regulation found in nearly all living organisms. Class I RNRs are composed of two proteins, a large α-subunit (R1) and a smaller β-subunit (R2) that exist as homodimers, that combine to form an active heterotetramer. Aquifex aeolicus is a hyperthermophilic bacterium with an unusual RNR encoding a 346-residue intein in the DNA sequence encoding its R2 subunit. We present the first structures of the A. aeolicus R1 and R2 (AaR1 and AaR2, respectively) proteins as well as the biophysical and biochemical characterization of active and inactive A. aeolicus RNR. While the active oligomeric state and activity regulation of A. aeolicus RNR are similar to those of other characterized RNRs, the X-ray crystal structures also reveal distinct features and adaptations. Specifically, AaR1 contains a β-hairpin hook structure at the dimer interface, which has an interesting π-stacking interaction absent in other members of the NrdAh subclass, and its ATP cone houses two ATP molecules. We determined structures of two AaR2 proteins: one purified from a construct lacking the intein (AaR2) and a second purified from a construct including the intein sequence (AaR2_genomic). These structures in the context of metal content analysis and activity data indicate that AaR2_genomic displays much higher iron occupancy and activity compared to AaR2, suggesting that the intein is important for facilitating complete iron incorporation, particularly in the Fe2 site of the mature R2 protein, which may be important for the survival of A. aeolicus in low-oxygen environments.

Journal Keywords: Peptides and proteins; Bacteria; Monomers; Crystal structure; Chemical structure

Diamond Keywords: Enzymes; Bacteria

Subject Areas: Biology and Bio-materials, Chemistry

Instruments: I03-Macromolecular Crystallography , I04-Macromolecular Crystallography

Added On: 28/12/2021 15:15


Discipline Tags:

Biochemistry Chemistry Structural biology Biophysics Life Sciences & Biotech

Technical Tags:

Diffraction Macromolecular Crystallography (MX)