Tuned SMC Arms Drive Chromosomal Loading of Prokaryotic Condensin

Frank Bürmann; Alrun Basfeld; Roberto Vazquez Nunez; Marie-Laure Diebold-Durand; Larissa Wilhelm; Stephan Gruber

doi:10.1016/j.molcel.2017.01.026

Tuned SMC Arms Drive Chromosomal Loading of Prokaryotic Condensin

Mol Cell. 2017 Mar 2;65(5):861-872.e9. doi: 10.1016/j.molcel.2017.01.026. Epub 2017 Feb 23.

Authors

Frank Bürmann¹, Alrun Basfeld¹, Roberto Vazquez Nunez², Marie-Laure Diebold-Durand¹, Larissa Wilhelm¹, Stephan Gruber³

Affiliations

¹ Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
² Department of Fundamental Microbiology, University of Lausanne, Bâtiment Biophore, 1015 Lausanne, Switzerland.
³ Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany; Department of Fundamental Microbiology, University of Lausanne, Bâtiment Biophore, 1015 Lausanne, Switzerland. Electronic address: stephan.gruber@unil.ch.

Abstract

SMC proteins support vital cellular processes in all domains of life by organizing chromosomal DNA. They are composed of ATPase "head" and "hinge" dimerization domains and a connecting coiled-coil "arm." Binding to a kleisin subunit creates a closed tripartite ring, whose ∼47-nm-long SMC arms act as barrier for DNA entrapment. Here, we uncover another, more active function of the bacterial Smc arm. Using high-throughput genetic engineering, we resized the arm in the range of 6-60 nm and found that it was functional only in specific length regimes following a periodic pattern. Natural SMC sequences reflect these length constraints. Mutants with improper arm length or peptide insertions in the arm efficiently target chromosomal loading sites and hydrolyze ATP but fail to use ATP hydrolysis for relocation onto flanking DNA. We propose that SMC arms implement force transmission upon nucleotide hydrolysis to mediate DNA capture or loop extrusion.

Keywords: ParB; SMC; Smc/ScpAB; chromosome segregation; cohesin; coiled coil; condensin; heptad repeat; kleisin; periodicity.

MeSH terms

Adenosine Triphosphatases / chemistry
Adenosine Triphosphatases / genetics
Adenosine Triphosphatases / metabolism*
Adenosine Triphosphate / metabolism
Bacillus subtilis / enzymology*
Bacillus subtilis / genetics
Bacterial Proteins / chemistry
Bacterial Proteins / genetics
Bacterial Proteins / metabolism*
Binding Sites
Cell Cycle Proteins / chemistry
Cell Cycle Proteins / genetics
Cell Cycle Proteins / metabolism*
Chromosomes, Bacterial / chemistry
Chromosomes, Bacterial / enzymology*
Chromosomes, Bacterial / genetics
DNA, Bacterial / chemistry
DNA, Bacterial / genetics
DNA, Bacterial / metabolism*
DNA-Binding Proteins / chemistry
DNA-Binding Proteins / genetics
DNA-Binding Proteins / metabolism*
Genetic Engineering / methods
High-Throughput Screening Assays
Hydrolysis
Multiprotein Complexes / chemistry
Multiprotein Complexes / genetics
Multiprotein Complexes / metabolism*
Mutation
Nucleic Acid Conformation
Protein Binding
Protein Conformation, alpha-Helical
Structure-Activity Relationship

Substances

Bacterial Proteins
Cell Cycle Proteins
DNA, Bacterial
DNA-Binding Proteins
Multiprotein Complexes
SMC protein, Bacteria
condensin complexes
Adenosine Triphosphate
Adenosine Triphosphatases

Grants and funding

260853/ERC_/European Research Council/International