The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Jakob Löndahl

Jakob Löndahl

Associate Professor / Senior Lecturer

Jakob Löndahl

Effects of Ice Nucleation Protein Repeat Number and Oligomerization Level on Ice Nucleation Activity

Author

  • M. L. Ling
  • H. Wex
  • S. Grawe
  • J. Jakobsson
  • J. Löndahl
  • S. Hartmann
  • K. Finster
  • T. Boesen
  • T. Šantl-Temkiv

Summary, in English

Ice nucleation active bacteria have attracted particular attention due to their unique ability to produce specific ice nucleation proteins (INpros), which are the most efficient ice nuclei known as they induce nucleation at temperatures close to 0°C. Our model bacterium Pseudomonas syringae strain R10.79 produced INpros containing 67 tandem repeats, forming the proposed ice-binding surface. To understand the role of the INpro repeats as well as the role of intermolecular interactions between INpros for their ice nucleation behavior, we produced a truncated version of the protein with only 16 tandem repeats (INpro16R). The purified INpro16R produced oligomers of varying sizes. Immersion freezing ice nucleation behavior of purified INpro16R was characterized by droplet-freezing assays and in the Leipzig Aerosol Cloud Interaction Simulator. Predominant INpro16R oligomers introduced into Leipzig Aerosol Cloud Interaction Simulator as single particles with diameters of 50 nm or 70 nm were ice nucleation active at temperatures of -26°C and -24°C, respectively. These are much lower temperatures compared to that of intact INpros (-12°C). The data clearly indicated that the number of repeats determines the ice nucleation temperature. In addition, ice nucleation between -9°C and -10°C, comparable to the activity of intact INpro, was caused by higher-order INpro16R oligomers. This supported previous observations that INpro oligomerization increases the ice-binding surface, thereby affecting ice nucleation activity. In conclusion, both repeat number and oligomerization contribute in a seemingly independent manner to the nucleation mechanism of INpros.

Department/s

  • Ergonomics and Aerosol Technology
  • MERGE: ModElling the Regional and Global Earth system
  • MERGE: ModElling the Regional and Global Earth System

Publishing year

2018-02-12

Language

English

Pages

1802-1810

Publication/Series

Journal of Geophysical Research: Atmospheres

Volume

123

Issue

3

Document type

Journal article

Publisher

Wiley-Blackwell

Topic

  • Meteorology and Atmospheric Sciences

Keywords

  • Bioaerosols
  • Precipitation

Status

Published

ISBN/ISSN/Other

  • ISSN: 2169-8996