This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. NLSL.SRLS.EXCH is a computer program for simulating multi-frequency CW spectra based on slowly relaxing local structure (SRLS) model with dynamic exchange. A service request was received from Dr Yuri Nesmelov on the usage of the NLSL.SRLS.EXCH program from ACERT website to study protein dynamics undergoing conformation exchange.