| Comments |
P.2312 left column bottom paragraph: "Next, [investigators] computed the dn/dc [protein refractive index increment] values for all 62,378 predicted protein sequences obtained from the University of California Santa Cruz (UCSC) genome browser for the human Feb. 2009 (GRCh37/hg19) assembly (Fig. 2). Interestingly, their distribution is very close to Gaussian, as if the refractive index of each residue were an independent random variable. Clearly, the considerable differences of the refractive properties of the amino acids average out for most natural protein sequences to an average of 0.1899 ml/g. The small standard deviation of 0.0030 ml/g confirms the expected similarity of refractive indices among most proteins. Similar distributions were obtained from the genome of different organisms that had mean values differing by less than the standard deviation of the distributions (Table 2). [They] observed that the predicted dn/dc value correlates well with the fraction of residues being Arg, Asp, Cys, His, Met, Phe, Trp, or Tyr, which are those with the highest eight values (Fig. 3)." See notes beneath table |