We present here HSQC experiments with improved sensitivity for signals in the presence of exchange broadening. During periods of coherence transfer through scalar coupling the experiments employ CPMG-derived pulse trains to reduce loss of dephasing of spin coherence due to chemical exchange. (15)N-(1)H gradient CPMG-HSQC and SE-CPMG-HSQC experiments have been developed and applied to complexes of lac repressor headpiece with operator DNA. Improved sensitivity is demonstrated for many protein backbone and side-chain resonances in the complex, markedly for signals of protons located at the protein-DNA interface. In addition, a significant increase in intensity is observed for arginine guanidino groups undergoing conformational exchange.