Synergistic perspectives-How single-molecule biophysics complement biochemical understanding.

Single-molecule biophysical techniques enable the study of biological systems by directly observing individual molecules and events, rather than measuring population averages. These approaches reveal transient states, rare events, conformational dynamics, and subpopulations that are often obscured in biochemical assays. The application of single-molecule methods has been limited by technical complexity and the need for specialized instrumentation. Recent standardization of protocols, methodologies, and platforms has lowered these barriers, enabling broader adoption and promoting interdisciplinary collaborations that facilitate integration into biochemical research. In this review, we discuss how ensemble biochemistry and single-molecule approaches are complementary, outline commonly used single-molecule techniques, and illustrate their relevance through two representative case studies: chromatin organization by SMC complexes and pathway choice during DNA double-strand break repair.