Devising Self-Assembled-Monolayers for Surface-Enhanced Infrared Spectroscopy of pH-Driven Poly-l-lysine Conformational Changes.
Langmuir
; 32(29): 7356-64, 2016 07 26.
Article
in En
| MEDLINE
| ID: mdl-27389421
ABSTRACT
Surface-enhanced infrared absorption spectroscopy (SEIRA) is applied to study protein conformational changes. In general, the appropriate functionalization of metal surfaces with biomolecules remains a challenge if the conformation and activity of the biomolecule shall be preserved. Here we present a SEIRA study to monitor pH-induced conformational changes of poly-l-lysine (PLL) covalently bound to a thin gold layer via self-assembled monolayers (SAMs). We demonstrate that the composition of the SAM is crucial. A SAM of 11-mercaptoundecanonic acid (MUA) can link PLL to the gold layer, but pH-driven conformational transitions were hindered compared to poly-l-lysine in solution. To address this problem, we devised a variety of SAMs, i.e., mixed SAMs of MUA with either octanethiol (OT) or 11-mercapto-1-undecanol (MUoL) and furthermore SAMs of MT(PEG)4 and NHS-PEG10k-SH. These mixed SAMs modify the surface properties by changing the polarity and the morphology of the surface present to nearby PLL molecules. Our experiments reveal that mixed SAMs of MUA-MUoL and SAMs of NHS-PEG10k-SH-MT(PEG)4 are suitable to monitor pH-driven conformational changes of immobilized PLL. These SAMs might be applicable for chemoselective protein immobilization in general.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Polyethylene Glycols
/
Polylysine
/
Sulfhydryl Compounds
/
Fatty Alcohols
/
Membranes, Artificial
Language:
En
Journal:
Langmuir
Journal subject:
QUIMICA
Year:
2016
Document type:
Article
Affiliation country:
Germany