Monitoring of protein conformation by high-performance size-exclusion liquid chromatography and scanning diode array second-derivative UV absorption spectroscopy.

Genetic methods now allow the rapid production of mutant proteins for structure-function analysis. To properly interpret any change in biologic activity resulting from modification in primary sequence, it is essential to monitor conformational changes resulting from mutations. Several methods allow low-resolution protein conformational analysis. One method, second-derivative UV absorption spectroscopy, is particularly useful for proteins containing tyrosine and/or tryptophan residues. Using high-performance size-exclusion liquid chromatography and scanning diode array detection we have demonstrated that it is possible to monitor the degree of aggregation as well as conformational perturbation for a series of interleukin-2 structural mutants. Furthermore, the combination of high-performance liquid chromatography and second-derivative UV absorption spectroscopy avoids a potential artifactual contribution in non-chromatographic analysis due to protein aggregation.