Dimerization of the type IV pilin from Pseudomonas aeruginosa strain K122-4 results in increased helix stability as measured by time-resolved hydrogen-deuterium exchange

• Published in: Structural dynamics (Melville, N.Y.) Vol. 3; no. 1; p. 012001
• Main Authors: Lento, Cristina, Wilson, Derek J, Audette, Gerald F
• Format: Journal Article
• Language: English
• Published: United States American Institute of Physics, Inc 01.01.2016; American Crystallographic Association; AIP Publishing LLC and ACA
• Subjects: Biofilms; Chromatography; Deuterium; Dimerization; Equilibrium; Gram-positive bacteria; Hydrogen; Mass spectrometry; Monomers; Oligomerization; Proteins; Scientific imaging; SPECIAL TOPIC: PROTEIN DYNAMICS; Time measurement
• ISSN: 2329-7778; 2329-7778
• DOI: 10.1063/1.4929597

Truncated pilin monomers from Pseudomonas aeruginosa strain K122-4 (ΔK122) have been shown to enter a monomer-dimer equilibrium in solution prior to oligomerization into protein nanotubes. Here, we examine the structural changes occurring between the monomeric and dimeric states of ΔK122 using time-resolved hydrogen-deuterium exchange mass spectrometry. Based on levels of deuterium uptake, the N-terminal α-helix and the loop connecting the second and third strands of the anti-parallel β-sheet contribute significantly to pilin dimerization. Conversely, the antiparallel β-sheet and αβ loop region exhibit increased flexibility, while the receptor binding domain retains a rigid conformation in the equilibrium state.