Solution Nuclear Magnetic Resonance Structure of Membrane-Integral Diacylglycerol Kinase
Wade D. Van Horn,1,*
Hak-Jun Kim,1,2,*
Charles D. Ellis,1
Arina Hadziselimovic,1
Endah S. Sulistijo,1
Murthy D. Karra,1
Changlin Tian,1,3
Frank D. Sönnichsen,4
Charles R. Sanders1,
Escherichia coli diacylglycerol kinase (DAGK) represents a family
of integral membrane enzymes that is unrelated to all other
phosphotransferases. We have determined the three-dimensional
structure of the DAGK homotrimer with the use of solution nuclear
magnetic resonance. The third transmembrane helix from each
subunit is domain-swapped with the first and second transmembrane
segments from an adjacent subunit. Each of DAGK’s three
active sites resembles a portico. The cornice of the portico
appears to be the determinant of DAGK’s lipid substrate
specificity and overhangs the site of phosphoryl transfer near
the water-membrane interface. Mutations to cysteine that caused
severe misfolding were located in or near the active site, indicating
a high degree of overlap between sites responsible for folding
and for catalysis.
1 Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA.
2 Korea Polar Research Institute, Incheon 406-840, Korea.
3 School of Life Science, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.
4 Otto Diels Institute for Organic Chemistry, Christian Albrechts University of Kiel, D-24098 Kiel, Germany.
* These authors contributed equally to this work.
To whom correspondence should be addressed. E-mail: chuck.sanders{at}vanderbilt.edu
