||Ainavarapu SR et al., Contour length and refolding rate of a small protein controlled by engineered disulfide bonds. Biophys J. 2007 Jan 1 92(1):225-33 p.229 right column top paragraphPubMed ID17028145
|| B.A. Katz, A. Kossiakoff The crystallographically determined structures of atypical strained disulfides engineered into subtilisin J. Biol. Chem., 261 (1986), pp. 15480-15485PubMed ID3096989
||P.229 right column top paragraph: "The assumption is that the intercept for the ΔLr data in Fig. 4 A corresponds to the distance between the α-carbon atoms of the cysteines, LSS, through the disulfide bond (Cα-Cβ-S-S-Cβ-Cα). However, the measured value of 4.3 aa × lr = 18 Å is in excess of the range expected from the average crystallographic measurement of disulfide bonds (5.5 Å) in proteins (primary source), suggesting that further elements are present in the protein structure."