pH responsive microdomain formation in a De Novo polypeptide

✍ Scribed by Mark Logan; Gordon Cannon; Charles L. McCormick

• Publisher: Wiley (John Wiley & Sons)
• Year: 1997
• Tongue: English
• Weight: 204 KB
• Volume: 41
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/(sici)1097-0282(19970415)41:5<521::aid-bip4>3.0.co;2-o

✦ Synopsis

Recombinant DNA technology has been employed to produce a polypeptide capable of forming pH responsive hydrophobic microdomains. The design of this peptide is based upon an idealized conceptual model in which electrostatic, hydrophobic, and hydration forces are responsible for the association of amphipathic a-helical elements. Reduction in solution pH is responsible for reducing electrostatic repulsions between similarly charged residues, promoting the hydrophobic collapse of helical elements. A polymerizable synthetic element (dn3l) has been synthesized and inserted into an appropriate expression vector. A clone containing a single copy of the dn31 gene (designated dn3lx1) was isolated and the corresponding gene product DN3Lx1 isolated. The physical properties of DN3Lx1 were examined in solution by gel filtration chromatography, CD, and fluorescence probe analysis. It was determined that DN3Lx1 self-associates in solution with the degree of aggregation dependent on pH and ionic strength. An initial objective of this work was to examine domain organization in higher molecular weight species containing ten or more repetitive sequences. However, attempts to express multiple repeats of DN3Lxn from concatemers were unsuccessful.