VOL. 2, No. 2, January 2005

J. C. Biro and A. M. Biro [2005] Med Hypotheses Res 2: 347-355.

Prediction of Stabilizing Electrostatic Interactions
Between Residues in Collagens

J. C. Biro* and A. M. Biro

Karolinska Institute, Stockholm, Sweden (J.C.B.) and Homulus Informatics, 88 Howard,
#1205, 94 105 CA, USA (A.M.B.)

Abstract. All collagen sequences have a distinctive signature, described by the
X-Y-Gly formula indicating that any amino acid might be present at X and Y positions, in
many combinations, while the third position is fixed and invariably glycine. The unique
periodic nature of these sequences makes it possible to perform a reliable statistical study
on the physico-chemical properties of amino acids at X and Y positions. In this study we
have phase separated twenty different main human collagen sequences into three
subsequences each. We have found that the X-Y-Gly formula is frequently corrupted by
phase shifts caused by deletion of a glycine codon. The overall average charge of amino
acids at X positions is always negative, while at Y positions it is always positive. No
exception was found. This indicates the periodic nature of collagens even at X and Y
positions and predicts a pattern-related interaction in and between collagen triple-helices.

*Address all correspondence to: Dr. Jan C. Biro, 88 Howard, #1205, San Francisco,94 105
CA, USA. Phone: 1-415-777-1443. E-Mail:

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