Park SR, Hauver J, Zhang Y, Revyakin A, Coleman RA, Tjian R, Chu S, Pertsinidis A. A Single-Molecule Surface-Based Platform to Detect the Assembly and Function of the Human RNA Polymerase II Transcription Machinery.
Structure 2020;
28:1337-1343.e4. [PMID:
32763141 DOI:
10.1016/j.str.2020.07.009]
[Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/08/2020] [Accepted: 07/21/2020] [Indexed: 01/28/2023]
Abstract
Single-molecule detection and manipulation is a powerful tool for unraveling dynamic biological processes. Unfortunately, success in such experiments is often challenged by tethering the biomolecule(s) of interest to a biocompatible surface. Here, we describe a robust surface passivation method by dense polymer brush grafting, based on optimized polyethylene glycol (PEG) deposition conditions, exactly at the lower critical point of an aqueous biphasic PEG-salt system. The increased biocompatibility achieved, compared with PEG deposition in sub-optimal conditions away from the critical point, allowed us to successfully detect the assembly and function of a large macromolecular machine, a fluorescent-labeled multi-subunit, human RNA Polymerase II Transcription Pre-Initiation Complex, on single, promoter-containing, surface-immobilized DNA molecules. This platform will enable probing the complex biochemistry and dynamics of large, multi-subunit macromolecular assemblies, such as during the initiation of human RNA Pol II transcription, at the single-molecule level.
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