Title |
The crystal structure of methanol dehydrogenase, a quinoprotein from the marine methylotrophic bacterium Methylophaga aminisulfidivorans MPT |
Author |
Thinh-Phat Cao1, Jin Myung Choi1, Si Wouk Kim2, and Sung Haeng Lee1* |
Address |
1Department of Cellular and Molecular Medicine, Chosun University School of Medicine, Gwangju 61452, Republic of Korea, 2Department of Environmental Engineering, Chosun University, Gwangju 61452, Republic of Korea |
Bibliography |
Journal of Microbiology, 56(4),246–254, 2018,
|
DOI |
10.1007/s12275-018-7483-y
|
Key Words |
methanol dehydrogenase, methanol oxidizing system,
pyrroloquinoline quinone, Mg2+, marine bacterium |
Abstract |
The first crystal structure of a pyrroloquinoline quinone
(PQQ)-dependent methanol dehydrogenase (MDH) from
a marine methylotrophic bacterium, Methylophaga aminisulfidivorans
MPT (MDHMas), was determined at 1.7 Å resolution.
The active form of MDHMas (or MDHIMas) is a heterotetrameric
α2β2, where each β-subunit assembles on one side of
each of the α-subunits, in a symmetrical fashion, so that two
β-subunits surround the two PQQ-binding pockets on the
α-subunits. The active site consists of a PQQ molecule surrounded
by a β-propeller fold for each α-subunit. Interestingly,
the PQQ molecules are coordinated by a Mg2+ ion,
instead of the Ca2+ ion that is commonly found in the terrestrial
MDHI, indicating the efficiency of osmotic balance
regulation in the high salt environment. The overall interaction
of the β-subunits with the α-subunits appears tighter than
that of terrestrial homologues, suggesting the efficient maintenance
of MDHIMas integrity in the sea water environment
to provide a firm basis for complex formation with MxaJMas
or Cyt cL. With the help of the features mentioned above, our
research may enable the elucidation of the full molecular mechanism
of methanol oxidation by taking advantage of marine
bacterium-originated proteins in the methanol oxidizing
system (mox), including MxaJ, as the attainment of these proteins
from terrestrial bacteria for structural studies has not
been successful. |