Title
Biophysical characterization of soluble Pseudomonas syringae ice nucleation protein InaZ fragments
Author
Yujin Han, HyoJin Song, Chang Woo Lee, Nguyễn Hoàng Ly, Sang-Woo Joo, Jun Hyuck Lee, Soon-Jong Kim, SangYoun Park
Year
2017
Journal
International Journal of Biological Macromolecules
Abstract
Ice nucleation protein (INP) with its functional domain consisting of multiple 48-residue repeat units effectively induces super-cooled water into ice. Circular dichroism and infrared deconvolution analyses on a soluble 240-residue fragment of Pseudomonas syringae InaZ (InaZ240) containing five 48-residue repeat units indicated that it is mostly composed of β-sheet and random coil. Analytical ultracentrifugation suggested that InaZ240 behaves as a monomer of an elongated ellipsoid. However, InaZ240 showed only minimum ice binding compared to anti-freeze proteins. Other P. syringae InaZ proteins with more 48-residue repeat units were made, in which the largest soluble fragment obtainable was an InaZ with twelve 48-residue repeat units. Size-exclusion chromatography analyses further suggested that the overall shape of the expressed InaZ fragments is pH-dependent, which becomes compact as the numbers of 48-residue repeat unit increase.
Instrument
J-810
Keywords
Circular dichroism, Secondary structure, Biochemistry