WWWWhy does nature stutter? A survey of strands of repeated amino acids

Human stuttering is a simple example of the repetition of sounds or symbols, sometimes associated with single letters, and may be used to illustrate the amazing repetition of amino acids (symbolized by a letter, e.g. W) in proteins. A survey of available databases with highly improbable strings of single amino acids is tabulated. This paper concludes with a challenge to the crystallographic community to probe the structural origins of the structure-function relationship in this neglected area. When nature stutters, we should pay attention.