Chitoporin from Serratia marcescens : recombinant expression, purification and crystallization

DOI: 10.1107/S2053230X20013874

Authors: Rawiporn Amornloetwattana (Vidyasirimedhi Institute of Science and Technology) , Robert Robinson (Vidyasirimedhi Institute of Science and Technology; Okayama University) , Hannadige Sasimali Madusanka Soysa (Sabaragamuwa University of Sri Lanka) , Bert Van Den Berg (Newcastle University) , Wipa Suginta (Vidyasirimedhi Institute of Science and Technology)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acta Crystallographica Section F Structural Biology Communications , VOL 76 , PAGES 536 - 543

State: Published (Approved)
Published: November 2020

Abstract: Serratia marcescens is an opportunistic pathogen that commonly causes hospital-acquired infections and can utilize chitin-enriched nutrients as an alternative energy source. This study reports the identification of a chitoporin (ChiP), termed SmChiP, from the outer membrane of S. marcescens. Sequence alignment with genetically characterized ChiPs suggests that SmChiP is more closely related to the monomeric EcChiP from Escherichia coli than to the trimeric VhChiP from Vibrio campbellii. A single crystal of SmChiP grown under the condition 22%(w/v) PEG 8000, 0.1 M calcium acetate, 0.1 M MES pH 6.0 diffracted X-ray synchrotron radiation to 1.85 Å resolution. SmChiP co-crystallized with chitohexaose under the condition 19%(w/v) PEG 1500, 2 M ammonium phosphate monobasic, 0.1 M HEPES pH 7.0 diffracted X-rays to 2.70 Å resolution. Preliminary crystallographic analysis shows that both SmChiP crystal forms contain one molecule per asymmetric unit and that they belong to the tetragonal space groups P42212 and P41212, respectively. The SmChiP crystal has unit-cell parameters a = 82.97, b = 82.97, c = 189.53 Å, α = β = γ = 90°, while the crystal of SmChiP in complex with chitohexaose has unit-cell parameters a = 73.24, b = 73.24, c = 213.46 Å, α = β = γ = 90°. Initial assessment of the complex structure clearly revealed electron density for the sugar ligand. Structure determination of SmChiP in the absence and presence of chitohexaose should reveal the molecular basis of chitin utilization by S. marcescens.

Journal Keywords: chitin; chitoporin; outer membrane proteins; Serratia marcescens; sugar transport; chitoligosaccharides; sugar-specific porins

Subject Areas: Biology and Bio-materials


Instruments: I04-1-Macromolecular Crystallography (fixed wavelength)