Proton Magnetic Resonance of Proteins Fully Deuterated except for ¹ H-Leucine Side Chains

Abstract

The fully deuterated proteins C-phycocyanin, C-phycoerythrin, and cytochrome c have been obtained by biosynthesis with the leucine side chains, and only the leucine side chains, of normal ((1)H) isotopic composition. In these (isotopic hybrid) proteins, proton magnetic resonance analysis shows that the (1)H-leucine side chains are in a variety of environments. During protein biosynthesis, the alpha hydrogen of leucine is exchanged with a hydrogen ((2)H) from the aqueous medium.