About

David Blair is a Professor of Biological Sciences at the University of Utah. His research focuses on bacterial motility, specifically the structure and molecular mechanism of the bacterial flagellar motor. He studies how bacteria swim using flagella, which are helical propellers driven by rotary motors in the cell membrane that can turn at speeds of 100,000 rpm or faster by obtaining energy from the membrane ion gradient. His work investigates how the flagellar motor controls direction and switching, and how the assembly and operation of the flagellum are energized and regulated. Blair's research also encompasses the process of flagellar assembly, including the active transport of protein subunits via a specific secretion apparatus, and the energy sources that drive this export process. His team has contributed to understanding the structure of the flagellar basal body, the organization of key proteins involved in rotation and switching, and the molecular mechanisms underlying protein export during flagellum assembly. His work extends to related systems such as the injectisome used by pathogenic bacteria to deliver virulence factors into host cells. Blair's contributions include solving structures of proteins involved in rotation, developing models for the rotor, and elucidating the energy mechanisms of flagellar export, advancing the understanding of biological energy conversions at membranes.

Research topics

• Biology
• Biochemistry
• Chemistry
• Cell biology
• Biophysics
• Engineering
• Microbiology
• Stereochemistry

Selected publications

• Control of membrane barrier during bacterial type-III protein secretion

  Nature Communications · 2021 · 21 citations

  • Cell biology
  • Chemistry
  • Microbiology

  Type-III secretion systems (T3SSs) of the bacterial flagellum and the evolutionarily related injectisome are capable of translocating proteins with a remarkable speed of several thousand amino acids per second. Here, we investigate how T3SSs are able to transport proteins at such a high rate while preventing the leakage of small molecules. Our mutational and evolutionary analyses demonstrate that an ensemble of conserved methionine residues at the cytoplasmic side of the T3SS channel create a deformable gasket (M-gasket) around fast-moving substrates undergoing export. The unique physicochemical features of the M-gasket are crucial to preserve the membrane barrier, to accommodate local conformational changes during active secretion, and to maintain stability of the secretion pore in cooperation with a plug domain (R-plug) and a network of salt-bridges. The conservation of the M-gasket, R-plug, and salt-bridge network suggests a universal mechanism by which the membrane integrity is maintained during high-speed protein translocation in all T3SSs.

  DOI

• Controlling membrane barrier during bacterial type-III protein secretion

  bioRxiv (Cold Spring Harbor Laboratory) · 2020 · 3 citations

  • Biology
  • Cell biology
  • Biophysics

  Type-III secretion systems (T3SSs) of the bacterial flagellum and the evolutionarily related injectisome are capable of translocating proteins with a remarkable speed of several thousand amino acids per second. Here, we investigated how T3SSs are able to transport proteins at such a high rate while preventing the leakage of small molecules. Our mutational and evolutionary analyses demonstrate that an ensemble of conserved methionine residues at the cytoplasmic side of the T3SS channel create a deformable gasket (M-gasket) around fast-moving substrates undergoing export. The unique physicochemical features of the M-gasket are crucial to preserve the membrane barrier, to accommodate local conformational changes during active secretion, and to maintain stability of the secretion pore in cooperation with a plug domain (R-plug) and a network of salt-bridges. The conservation of the M-gasket, R-plug, and salt-bridge network suggests a universal mechanism by which the membrane integrity is maintained during high-speed protein translocation in all T3SSs.

  DOI

• Allosteric Priming of E. coli CheY by the Flagellar Motor Protein FliM

  Biophysical Journal · 2020 · 17 citations

  • Chemistry
  • Biophysics
  • Stereochemistry
  DOI

Recent grants

• Structure and Mechanism of the Flagellar Switch

  NIH · $4.1M · 2003–2019

• NIH Grant R01GM061145

  NIH · $685k · 2004

• NIH Grant R01GM046683

  NIH · $798k · 1999

• NIH Grant R01EB002041

  NIH · $248k · 2004

• NIH Grant R01GM087260

  NIH · $485k · 2011

Frequent coauthors

• Sunney I. Chan

  Institute of Chemistry, Academia Sinica

  16 shared

• Koushik Paul

  11 shared

• Thibaud T. Renault

  Inserm

  11 shared

• Eun A Kim

  Sahmyook University

  8 shared

• Harry B. Gray

  California Institute of Technology

  7 shared

• Marc Erhardt

  Charité - Universitätsmedizin Berlin

  7 shared

• Howard C. Berg

  7 shared

• Craig T. Martin

  University of Massachusetts Amherst

  6 shared

Education

• B.A.

  Princeton University

• Ph.D.

  California Institute of Technology

Similar researchers at University of Utah

• Teruo Okanoh-160
• Mario Capecchih-134
• Gerald J. Gleichh-119
• Michael Allen Pulsipherh-110
• Alfred K. Cheungh-106