Puzzle pieces defined: locating common packing units in tertiary protein contacts

Puzzle pieces are defined as small packing units which make up the unique tertiary interactions in proteins. Anti-parallel and perpendicular helix-helix contacts were broken down into basic puzzle-piece pairs in order to study the traits of such contacts: their limited geometry, preferred residue involvement, residue conformation and other common constraints. These traits can then be used for continued comparison of other protein structures, improving models of and designing proteins de novo and, in time, predicting 3D structure from primary sequence. Results from a small (100 proteins) database of anti-parallel helix-helix contacts and from preliminary work on a large database (600 proteins) of perpendicular helix-helix contacts are presented.

Myoglobinemia and endurance exercise: a study of twenty-five participants in a triathlon competition

Twenty-five athletes competing in a triathlon, an endurance competition, were studied to determine the relationship of sustained muscle exertion with myoglobinemia and clinical rhabdomyolysis. Of 24 athletes who completed the event, each individual demonstrated a dramatic rise and fall in serum myoglobin over a 24 hour period, with an average peak level of 842 ng/ml. While all subjects exhibited symptoms of myalgia after exertion, none required hospitalization. A significant correlation was demonstrated with average serum myoglobin and finishing time (P less than 0.0125) and postexercise temperature (P less than 0.05). Appropriate training of individuals, whether athletes or military recruits, appears to be an important factor in reducing myoglobinemia. Exercise-induced myoglobinemia appears to be dependent on intensity of athletic performance, measured as a function of time, distance, and activity performed. The athletes who finished first had the highest levels of myoglobinemia.