Mycobacterium tuberculosis FtsX extracellular domain activates the peptidoglycan hydrolase, RipC.
Bacterial growth and cell division are coordinated with hydrolysis of the peptidoglycan (PG) layer of the cell wall, but the mechanisms of regulation of extracellular PG hydrolases are not well understood. Here we report the biochemical, structural, and genetic analysis of the Mycobacterium tuberculosis homolog of the transmembrane PG-hydrolase regulator, FtsX. The purified FtsX extracellular domain binds the PG peptidase Rv2190c/RipC N-terminal segment, causing a conformational change that activates the enzyme. Deletion of ftsEX and ripC caused similar phenotypes in Mycobacterium smegmatis, as expected for genes in a single pathway. The crystal structure of the FtsX extracellular domain reveals an unprecedented fold containing two lobes connected by a flexible hinge. Mutations in the hydrophobic cleft between the lobes reduce RipC binding in vitro and inhibit FtsX function in M. smegmatis. These studies suggest how FtsX recognizes RipC and support a model in which a conformational change in FtsX links the cell division apparatus with PG hydrolysis.
QB3 Institute, California Institute for Quantitative Bioscience, and.
Daniela
D
Mavrici
Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115;
Mohlopheni J
MJ
Marakalala
Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158-2330;Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; and.
James M
JM
Holton
QB3 Institute, California Institute for Quantitative Bioscience, andDepartment of Molecular and Cell Biology, University of California, Berkeley, CA 94720;
Daniil M
DM
Prigozhin
Australian Synchrotron, Clayton, VIC 3168, Australia.
Christine L
CL
Gee
Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115;
Yanjia J
YJ
Zhang
Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115; erubin@hsph.harvard.edu.
Eric J
EJ
Rubin
QB3 Institute, California Institute for Quantitative Bioscience, andDepartment of Molecular and Cell Biology, University of California, Berkeley, CA 94720;
Tom
T
Alber
D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000201:enzymology; D018360:Crystallography, X-Ray; D004789:Enzyme Activation / Q000502:physiology; D006868:Hydrolysis; D020102:Mycobacterium smegmatis / Q000201:enzymology* / Q000235:genetics; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000235:genetics; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D015398:Signal Transduction / Q000502:physiology; D037521:Virulence Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; C102286:FtsX protein, bacteria; C578340:Rv2190c protein, Mycobacterium tuberculosis; D037521:Virulence Factors; D009238:N-Acetylmuramoyl-L-alanine Amidase
bacterial cell wall; divisome; extracellular signaling; long-range conformational change