TY - JOUR
T1 - Influence of heme propionates on the nitrite reductase activity of myoglobin
AU - Galinato, Mary Grace I.
AU - Trail, Aaron M.
AU - Steinbeck, Olivia R.
AU - Si, Zhuoyan
AU - Rodland, Anthony M.
AU - Gowen, Jaclyn
N1 - Funding Information:
MGIG would like to acknowledge Sigma Delta Epsilon-Graduate Women in Science for financial support, and Robert S. Fogle III for preliminary preparation of samples. AMR, JG, and ZS thank Penn State Behrend Undergraduate Research Grants Program for research funding on this project.
Publisher Copyright:
© 2021 Elsevier Inc.
PY - 2022/1
Y1 - 2022/1
N2 - The heme propionates in myoglobin (Mb) form a H-bonding network among several residues within its second-sphere coordination, providing a key structural role towards Mb's functional properties. Our work aims to understand the role of the heme propionates on the nitrite reductase (NiR) activity (e.g. reduction of NO2− to NO) of this globin by studying an artificial dimethylester heme-substituted horse heart Mb (DME-Mb). The minor structural change brought about by esterification of the heme propionates causes the NiR rate to increase by more than over two-fold (5.6 ± 0.1 M−1 s−1) relative to wildtype (wt) Mb (2.3 ± 0.1 M−1 s−1). The lower pKa observed in DME-Mb may enhance the tendency of His64 towards protonation, therefore increasing the NiR rate. In addition, the nitrite binding constant (Knitrite) for DME-MbIII is greater than wt MbIII (350 M−1 versus 120 M−1). The disparity in the NiR activity correlates with the differences in electrostatic behavior, which influences the system's reactivity towards the approaching NO2− ion, and thus the formation of the FeII-NO2− intermediate.
AB - The heme propionates in myoglobin (Mb) form a H-bonding network among several residues within its second-sphere coordination, providing a key structural role towards Mb's functional properties. Our work aims to understand the role of the heme propionates on the nitrite reductase (NiR) activity (e.g. reduction of NO2− to NO) of this globin by studying an artificial dimethylester heme-substituted horse heart Mb (DME-Mb). The minor structural change brought about by esterification of the heme propionates causes the NiR rate to increase by more than over two-fold (5.6 ± 0.1 M−1 s−1) relative to wildtype (wt) Mb (2.3 ± 0.1 M−1 s−1). The lower pKa observed in DME-Mb may enhance the tendency of His64 towards protonation, therefore increasing the NiR rate. In addition, the nitrite binding constant (Knitrite) for DME-MbIII is greater than wt MbIII (350 M−1 versus 120 M−1). The disparity in the NiR activity correlates with the differences in electrostatic behavior, which influences the system's reactivity towards the approaching NO2− ion, and thus the formation of the FeII-NO2− intermediate.
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U2 - 10.1016/j.jinorgbio.2021.111630
DO - 10.1016/j.jinorgbio.2021.111630
M3 - Article
C2 - 34688205
AN - SCOPUS:85117394600
SN - 0162-0134
VL - 226
JO - Journal of Inorganic Biochemistry
JF - Journal of Inorganic Biochemistry
M1 - 111630
ER -