Structural Characterization of Arginine Fingers: Identification of an Arginine Finger for the Pyrophosphatase dUTPases

TY - JOUR

T1 - Structural Characterization of Arginine Fingers: Identification of an Arginine Finger for the Pyrophosphatase dUTPases

AU - Nagy, Gergely N.

AU - Suardiaz, Reynier

AU - Lopata, Anna

AU - Ozohanics, Olivér

AU - Vékey, Károly

AU - Brooks, Bernard R.

AU - Leveles, Ibolya

AU - Toth, Judit

AU - Vértessy, Beáta G

AU - Rosta, Edina

PY - 2016/11/16

Y1 - 2016/11/16

N2 - Arginine finger is a highly conserved and essential residue in many GTPase and AAA+ ATPase enzymes that completes the active site from a distinct protomer, forming contacts with the γ-phosphate of the nucleotide. To date, no pyrophosphatase has been identified that employs an arginine finger fulfilling all the above properties, all essential arginine fingers are used to catalyze the cleavage of the γ-phosphate. Here, we identify and unveil the role of a conserved arginine residue in trimeric dUTPases that meets all the criteria established for arginine fingers. We found that the conserved arginine adjacent to the P-loop-like motif enables structural organization of the active site for efficient catalysis via its direct nucleotide coordination, while its direct electrostatic role in transition state stabilization is secondary. An exhaustive structure-based comparison of analogous, conserved arginines from nucleotide hydrolases and transferases revealed a consensus amino acid location and orientation for contacting the γ-phosphate of the substrate nucleotide. Despite the structurally equivalent position, functional differences between arginine fingers of dUTPases and NTPases are explained based on the unique chemistry performed by the pyrophosphatase dUTPases.

AB - Arginine finger is a highly conserved and essential residue in many GTPase and AAA+ ATPase enzymes that completes the active site from a distinct protomer, forming contacts with the γ-phosphate of the nucleotide. To date, no pyrophosphatase has been identified that employs an arginine finger fulfilling all the above properties, all essential arginine fingers are used to catalyze the cleavage of the γ-phosphate. Here, we identify and unveil the role of a conserved arginine residue in trimeric dUTPases that meets all the criteria established for arginine fingers. We found that the conserved arginine adjacent to the P-loop-like motif enables structural organization of the active site for efficient catalysis via its direct nucleotide coordination, while its direct electrostatic role in transition state stabilization is secondary. An exhaustive structure-based comparison of analogous, conserved arginines from nucleotide hydrolases and transferases revealed a consensus amino acid location and orientation for contacting the γ-phosphate of the substrate nucleotide. Despite the structurally equivalent position, functional differences between arginine fingers of dUTPases and NTPases are explained based on the unique chemistry performed by the pyrophosphatase dUTPases.

U2 - 10.1021/jacs.6b09012

DO - 10.1021/jacs.6b09012

M3 - Article

SN - 0002-7863

VL - 138

SP - 15035

EP - 15045

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

IS - 45

ER -