- Assistant Professor, Department of Food Science and Technology
The goal of Dr. Piepenbrink’s research program is to elucidate the molecular mechanisms by which bacteria interact with their surroundings; this includes host cells, abiotic surfaces, extracellular structures and, in particular, other bacteria. Dr. Piepenbrink’s group is approaching the basic question of how bacteria self-assemble into communities by applying the lenses of structural biology and biophysics to microbial surface structures.
These studies seek to explain the phenotypic differences between bacterial strains of similar genetic background; typically by comparing pathogenic bacteria to their commensal or environmental counterparts. The current focus is on type IV filaments, a class of extracellular appendages common to a wide range of bacteria, both Gram-positive and Gram-negative. To these ends, they pursue a variety of objectives: i) determining the high-resolution three-dimensional structures of the proteins and glycoproteins which make up extracellular assemblies, ii) using lower-resolution structural techniques in combination with molecular modeling to understand how subunits are assembled into extracellular superstructures, iii) identifying substrates for intermolecular interactions that underpin the adhesive activity of pili and other bacterial appendages and iv) elucidating the role of extracellular polymers, particularly protein fibers and polysaccharides, in promoting and stabilizing bacterial biofilms.
Piepenbrink KH, Sundberg EJ. Motility and adhesion through type IV pili in Gram-positive bacteria. Biochem Soc Trans. 2016 Dec 15;44(6):1659-1666. Review. PMID: 27913675
Piepenbrink KH, Lillehoj E, Harding CM, Labonte JW, Zuo X, Rapp CA, Munson RS Jr, Goldblum SE, Feldman MF, Gray JJ, Sundberg EJ. Structural Diversity in the Type IV Pili of Multidrug-resistant Acinetobacter. J Biol Chem. 2016 Oct 28;291(44):22924-22935. Epub 2016 Sep 15. PMID: 27634041
Maldarelli GA, Piepenbrink KH, Scott AJ, Freiberg JA, Song Y, Achermann Y, Ernst RK, Shirtliff ME, Sundberg EJ, Donnenberg MS, von Rosenvinge EC. Type IV pili promote early biofilm formation by Clostridium difficile. Pathog Dis. 2016 Aug;74(6). pii: ftw061. doi: 10.1093/femspd/ftw061. Epub 2016 Jun 30. PMID: 27369898
Piepenbrink KH, Maldarelli GA, Martinez de la Peña CF, Dingle TC, Mulvey GL, Lee A, von Rosenvinge E, Armstrong GD, Donnenberg MS, Sundberg EJ. Structural and evolutionary analyses show unique stabilization strategies in the type IV pili of Clostridium difficile. Structure. 2015 Feb 3;23(2):385-96. doi: 10.1016/j.str.2014.11.018. Epub 2015 Jan 15. PMID: 25599642
Piepenbrink KH, Maldarelli GA, de la Peña CF, Mulvey GL, Snyder GA, De Masi L, von Rosenvinge EC, Günther S, Armstrong GD, Donnenberg MS, Sundberg EJ. Structure of Clostridium difficile PilJ exhibits unprecedented divergence from known type IV pilins. J Biol Chem. 2014 Feb 14;289(7):4334-45. doi: 10.1074/jbc.M113.534404. Epub 2013 Dec 21. PMID: 24362261