A surgical instrument comprises an end effector including a pair of jaw members configured to move with respect to one another between an open configuration and a closed configuration for clamping tissue. At least one jaw member includes an elongate cam slot extending in a longitudinal direction over a substantial a length a tissue clamping surface of the at least one jaw member. A plurality of electrically isolated, and longitudinally spaced electrodes is supported by the tissue clamping surface and is configured to deliver electrosurgical energy to tissue. A reciprocating member engages the elongate cam slot and is extendable to a sealing position with respect to each of the electrodes to define a predetermined gap distance between a particular electrode and an opposing tissue clamping surface.