All Proteins Have a Basic Molecular Formula

This study proposes a basic molecular formula for all proteins. A total of 10,739 proteins belonging to 9 different protein groups classified on the basis of their functions were selected randomly. They included enzymes, storage proteins, hormones, signalling proteins, structural proteins, transport proteins, immunoglobulins or antibodies, motor proteins and receptor proteins. After obtaining the protein molecular formula using the ProtParam tool, the H/C, N/C, O/C, and S/C ratios were determined for each randomly selected sample. In this case, H, N, O, and S coefficients were specified per carbon atom. Surprisingly, the results demonstrated that H, N, O, and S coefficients for all 10,739 proteins are similar and highly correlated. This study demonstrates that despite differences in the structure and function, all known proteins have a similar basic molecular formula CnH1.58 ± 0.015nN0.28 ± 0.005nO0.30 ± 0.007nS0.01 ± 0.002n. The total correlation between all coefficients was found to be 0.9999.

Authors:

• Homa Torabizadeh

Keywords:

• Protein molecular formula
• Basic unit formula
• Protparam tool.

References:

[1] L. Jin, W. Fang, "On A comment on ÔÇÿPrediction of protein structural
classes by a new measure of information discrepancy," Comput. Biol.
Chem., vol. 33, no. 6, pp. 469-470,December. 2009.
[2] L. Palopoli, S. E. Rombo, G. Terracina, G. Tradigo, P. Veltri,
"Improving protein secondary structure predictions by prediction
fusion," Info. Fusion., vol. 10, no. 3, pp. 217-232, July. 2009.
[3] C.A. Ouzounis, R.M.R. Coulson, A.J. Enright, V. Kunin, J.B. Pereira-
Leal, "Classification schemes for protein structure and function," Nat.
Rev. Genet., vol. 4, no. 7, pp. 508-519, July. 2003.
[4] S.C. Rison, T.C. Hodgman, J.M. Thornton, "Comparison of functional
annotation schemes for genomes," Funct. Integr. Genomics., vol. 1, no.
1, pp. 56-69, May. 2000.
[5] http://proteincrystallography.org/protein/