Why inverse proteins are relatively abundant.

Studies have shown that inverse proteins are relatively abundant. In this work, we investigate the proposition that the repeat patterns they share with protein sequences explain this phenomenon. Using a new artificial set of peptide sequences which also display these features and a random set, we show that the presence of repeats contributes to protein sequence similarity. Further analysis confirms that most inverse proteins exhibit repeats. Therefore, we suggest the relative abundance of inverse proteins can be explained by the fact they display the same repeat structures and amino acid propensity of existing proteins.