Structural Diversity in the Type IV Pili of Multidrug-resistant Acinetobacter

Authors

Kurt H. Piepenbrink, Institute of Human Virology and Departments of MedicineFollow
Erik Lillehoj, University of Maryland
Christian M. Harding, Washington University School of Medicine
Jason W. Labonte, The Johns Hopkins University
Xiaotong Zuo, The Johns Hopkins University
Chelsea A. Rapp, University of Maryland School of Medicine
Robert S. Munson Jr, The Ohio State University College of Medicine
Simeon E. Goldblum, University of Maryland School of Medicine
Mario F. Feldman, Washington University School of Medicine
Jeffrey J. Gray, The Johns Hopkins University
Eric J. Sundberg, University of Maryland School of Medicine

Date of this Version

9-15-2016

Document Type

Article

Citation

THE JOURNAL OF BIOLOGICAL CHEMISTRY VOL. 291, NO. 44, pp. 22924 –22935, DOI 10.1074/jbc.M116.751099

Comments

OPEN ACCESS

Abstract

Acinetobacter baumannii is a Gram-negative coccobacillus found primarily in hospital settings that has recently emerged as a source of hospital-acquired infections. A. baumannii expresses a variety of virulence factors, including type IV pili, bacterial extracellular appendages often essential for attachment to host cells. Here, we report the high resolution structures of the major pilin subunit, PilA, from three Acinetobacter strains, demonstrating thatA. baumannii subsets produce morphologically distinct type IV pilin glycoproteins. We examine the consequences of this heterogeneity for protein folding and assembly as well as host-cell adhesion by Acinetobacter. Comparisons of genomic and structural data with pilin proteins from other species of soil gammaproteobacteria suggest that these structural differences stem from evolutionary pressure that has resulted in three distinct classes of type IVa pilins, each found in multiple species.