Original article: Susceptible Amino Acid Pairs in Variants in Human Collagen α 1(III) Chain Precursor

In a previous study we presented a technique to differentiate between randomly predictable and randomly unpredictable amino acid pairs. We have shown that all of 95 variants in human collagen α 1(I) chain precursor (CA11) occurred at randomly unpredictable amino acid pairs. To study whether this is unique for the human collagen α 1(I) chain precursor (CA11) or whether this is a more general principle we examined another human collagen precursor, the human collagen α 1(III) chain precursor (CA13), in which 106 variants have been documented. Interestingly, all of 106 variants occurred at randomly unpredictable amino acid pairs in human CA13. In conclusion, the observation that randomly unpredictable amino acid pairs are more susceptible to variation seems to be a more general principle for human collagen chain precursor proteins