Identification of protein domains on major pilin MrkA that affects the mechanical properties of Klebsiella pneumoniae type 3 fimbriae

Chia Han Chan, Feng Jung Chen, Ying Jung Huang, Shin Yu Chen, Kuo Liang Liu, Zhe Chong Wang, Hwei-Ling Peng, Tri Rung Yew, Cheng Hsien Liu, Gunn Guang Liou, Ken-Yuh Hsu, Hwan You Chang*, Long Hsu

*Corresponding author for this work

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

The Klebsiella pneumoniae type 3 fimbriae are mainly composed of MrkA pilins that assemble into a helixlike filament. This study determined the biomechanical properties of the fimbriae and analyzed 11 site-directed MrkA mutants to identify domains that are critical for the properties. Escherichia coli strains expressing type 3 fimbriae with an Ala substitution at either F34, V45, C87, G189, T196, or Y197 resulted in a significant reduction in biofilm formation. The E. coli strain expressing MrkAG189A remained capable of producing a normal number of fimbriae. Although F34A, V45A, T196A, and Y197A substitutions expressed on E. coli strains produced sparse quantities of fimbriae, no fimbriae were observed on the cells expressing MrkAC87A. Further investigations of the mechanical properties of the MrkAG189A fimbriae with optical tweezers revealed that, unlike the wild-type fimbriae, the uncoiling force for MrkAG189A fimbriae was not constant. The MrkAG189A fimbriae also exhibited a lower enthalpy in the differential scanning calorimetry analysis. Together, these findings indicate that the mutant fimbriae are less stable than the wild-type. This study has demonstrated that the C-terminal β strands of MrkA are required for the assembly and structural stability of fimbriae.

Original languageEnglish
Pages (from-to)7428-7435
Number of pages8
JournalLangmuir
Volume28
Issue number19
DOIs
StatePublished - 15 May 2012

Fingerprint Dive into the research topics of 'Identification of protein domains on major pilin MrkA that affects the mechanical properties of Klebsiella pneumoniae type 3 fimbriae'. Together they form a unique fingerprint.

Cite this