Certain embodiments of the invention can provide systems and methods for disabling a contactless transaction device. The kits can comprise a plurality of binding elements for cell surface markers, and a plurality of binding elements for state-specific intracellular markers. The user terminal has the capability of either initiating or receiving packet data messages. The wireless radio device configures the operating parameters of the wireless device in accordance with configuration parameters associated with the determined regulatory domain. Also provided are methods for the preparation of these mutants, methods for the use of these mutants, methods for rationally designing new polypeptide mutants, and methods for screening mutants polypeptides to identify novel EGF mutants with desirable biological activities.