6p5t

Publication Abstract from PubMed

Surface layers (S-layers) are crystalline protein coats surrounding microbial cells. S-layer proteins (SLPs) regulate their extracellular self-assembly by crystallizing when exposed to an environmental trigger. However, molecular mechanisms governing rapid protein crystallization in vivo or in vitro are largely unknown. Here, we demonstrate that the Caulobacter crescentus SLP readily crystallizes into sheets in vitro via a calcium-triggered multistep assembly pathway. This pathway involves 2 domains serving distinct functions in assembly. The C-terminal crystallization domain forms the physiological 2-dimensional (2D) crystal lattice, but full-length protein crystallizes multiple orders of magnitude faster due to the N-terminal nucleation domain. Observing crystallization using a time course of electron cryo-microscopy (Cryo-EM) imaging reveals a crystalline intermediate wherein N-terminal nucleation domains exhibit motional dynamics with respect to rigid lattice-forming crystallization domains. Dynamic flexibility between the 2 domains rationalizes efficient S-layer crystal nucleation on the curved cellular surface. Rate enhancement of protein crystallization by a discrete nucleation domain may enable engineering of kinetically controllable self-assembling 2D macromolecular nanomaterials.

A bacterial surface layer protein exploits multistep crystallization for rapid self-assembly.,Herrmann J, Li PN, Jabbarpour F, Chan ACK, Rajkovic I, Matsui T, Shapiro L, Smit J, Weiss TM, Murphy MEP, Wakatsuki S Proc Natl Acad Sci U S A. 2020 Jan 7;117(1):388-394. doi:, 10.1073/pnas.1909798116. Epub 2019 Dec 17. PMID:31848245^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.