TY - JOUR
T1 - Characterization of anammox hydrazine dehydrogenase, a Key -producing enzyme in the global nitrogen cycle
AU - Maalcke, Wouter J.
AU - Reimann, Joachim
AU - De Vries, Simon
AU - Butt, Julea N.
AU - Dietl, Andreas
AU - Kip, Nardy
AU - Mersdorf, Ulrike
AU - Barends, Thomas R M
AU - Jetten, Mike S M
AU - Keltjens, Jan T.
AU - Kartal, Boran
PY - 2016/8/12
Y1 - 2016/8/12
N2 - Anaerobic ammonium-oxidizing (anammox) bacteria derive their energy for growth from the oxidation of ammonium with nitrite as the electron acceptor. N2 , the end product of this metabolism, is produced from the oxidation of the intermediate, hydrazine (N2 H4 ). Previously, we identified N2 -producing hydrazine dehydrogenase (KsHDH) from the anammox organism Kuenenia stuttgartiensis as the gene product of kustc0694 and determined some of its catalytic properties. In the genome of K. stuttgartiensis, kustc0694 is one of 10 paralogs related to octaheme hydroxylamine (NH2OH) oxidoreductase (HAO). Here, we characterized KsHDH as a covalently cross-linked homotrimeric octaheme protein as found for HAO and HAO-related hydroxylamine-oxidizing enzyme kustc1061 from K. stuttgartiensis. Interestingly, the HDH trimers formed octamers in solution, each octamer harboring an amazing 192 c-type heme moieties. Whereas HAO and kustc1061 are capable of hydrazine oxidation as well, KsHDH was highly specific for this activity. To understand this specificity, we performed detailed amino acid sequence analyses and investigated the catalytic and spectroscopic (electronic absorbance, EPR) properties of KsHDH in comparison with the well defined HAO and kustc1061. We conclude that HDH specificity is most likely derived from structural changes around the catalytic heme 4 (P460 ) and of the electron-wiring circuit comprising seven His/His-ligated c-type hemes in each subunit. These nuances make HDH a globally prominent N2-producing enzyme, next to nitrous oxide (N2O) reductase from denitrifying microorganisms.
AB - Anaerobic ammonium-oxidizing (anammox) bacteria derive their energy for growth from the oxidation of ammonium with nitrite as the electron acceptor. N2 , the end product of this metabolism, is produced from the oxidation of the intermediate, hydrazine (N2 H4 ). Previously, we identified N2 -producing hydrazine dehydrogenase (KsHDH) from the anammox organism Kuenenia stuttgartiensis as the gene product of kustc0694 and determined some of its catalytic properties. In the genome of K. stuttgartiensis, kustc0694 is one of 10 paralogs related to octaheme hydroxylamine (NH2OH) oxidoreductase (HAO). Here, we characterized KsHDH as a covalently cross-linked homotrimeric octaheme protein as found for HAO and HAO-related hydroxylamine-oxidizing enzyme kustc1061 from K. stuttgartiensis. Interestingly, the HDH trimers formed octamers in solution, each octamer harboring an amazing 192 c-type heme moieties. Whereas HAO and kustc1061 are capable of hydrazine oxidation as well, KsHDH was highly specific for this activity. To understand this specificity, we performed detailed amino acid sequence analyses and investigated the catalytic and spectroscopic (electronic absorbance, EPR) properties of KsHDH in comparison with the well defined HAO and kustc1061. We conclude that HDH specificity is most likely derived from structural changes around the catalytic heme 4 (P460 ) and of the electron-wiring circuit comprising seven His/His-ligated c-type hemes in each subunit. These nuances make HDH a globally prominent N2-producing enzyme, next to nitrous oxide (N2O) reductase from denitrifying microorganisms.
UR - http://www.scopus.com/inward/record.url?scp=84979896716&partnerID=8YFLogxK
U2 - 10.1074/jbc.M116.735530
DO - 10.1074/jbc.M116.735530
M3 - Article
AN - SCOPUS:84979896716
SN - 0021-9258
VL - 291
SP - 17077
EP - 17092
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 33
ER -