Linking Protein Mass with Function via Organismal Massome Networks

With the human genome sequenced, attention has been shifting to proteins and their function. Several technologies including mass spectrometry and gel electrophoresis have traditionally been used to study proteins. These technologies rely on proteins' masses to characterize and/or identify them. Once identified, the discovered proteins' are often analyzed for their functional relevance. In this paper, we present an alternative approach to studying protein function directly, based on protein mass. By analyzing proteins with similar mass ranges (bins), we discovered that certain biological functions are associated with specific mass bins more frequently than would be expected by chance. Biological functional classes found in this manner could be seen across the three examined organisms: human, worm and fly. We found no sequence-based homology across significant mass-function proteins in the three different organisms. This investigation leads to useful property that the mass-based biological functional classes are preserved across the organisms. Thus, this paper describes a potential constraint for evolution of similar function based on mass constraints. Finally, this work yields a roadmap for experimental design for functional exploration of proteomes in mass-based technologies such as gel electrophoresis and mass spectrometry.