Features critical for membrane binding revealed by DivIVA crystal structure.
DivIVA is a conserved protein in Gram-positive bacteria that localizes at the poles and division sites, presumably through direct sensing of membrane curvature. DivIVA functions as a scaffold and is vital for septum site selection during vegetative growth and chromosome anchoring during sporulation. DivIVA deletion causes filamentous growth in Bacillus subtilis, whereas overexpression causes hyphal branching in Streptomyces coelicolor. We have determined the crystal structure of the N-terminal (Nt) domain of DivIVA, and show that it forms a parallel coiled-coil. It is capped with two unique crossed and intertwined loops, exposing hydrophobic and positively charged residues that we show here are essential for membrane binding. An intragenic suppressor introducing a positive charge restores membrane binding after mutating the hydrophobic residues. We propose that the hydrophobic residues insert into the membrane and that the positively charged residues bind to the membrane surface. A low-resolution crystal structure of the C-terminal (Ct) domain displays a curved tetramer made from two parallel coiled-coils. The Nt and Ct parts were then merged into a model of the full length, 30 nm long DivIVA protein.
Oliva
Maria A
MA
MRC Laboratory of Molecular Biology, Cambridge, UK.
Halbedel
Sven
S
Freund
Stefan M
SM
Dutow
Pavel
P
Leonard
Thomas A
TA
Veprintsev
Dmitry B
DB
Hamoen
Leendert W
LW
Löwe
Jan
J
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000737:chemistry* / Q000502:physiology*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D013489:Suppression, Genetic
D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; C104636:DivIVA protein, bacteria