title: Intraresidue distribution of energy in proteins.
abstract: Boltzmann-like distributions appear in many properties and energy-related quantities of proteins. A few examples are hydrophobicity, various types of side-chain/side-chain interactions, proline isomerization, hydrogen bonds, internal cavities, interactions at the level of specific atom types, and the propensity of the phi/'phi' ratio. Here, we conjecture that the Boltzmann hypothesis also holds for the intra-residue energy distribution. We confirm the conjecture by calculating the energies of 41,672 residues of the structures of highly resolved proteins, where at least 12 out of 20 naturally occurring amino acids follow Boltzmann's law. We further examine the entire set of all residue energies and find that the convolution of the individual distributions gives a Poisson function, which is followed by approximately 50% of individual proteins' structures.
authors.affiliation: Dipartimento di Chimica "G. Ciamician" and Dipartimento di Biologia, Università di Bologna, via F. Selmi 2, 40126 Bologna, Italy.
authors.forename: Bruno
authors.initials: B
authors.lastname: Trebbi
authors.forename: Marianna
authors.initials: M
authors.lastname: Fanti
authors.forename: Ivan
authors.initials: I
authors.lastname: Rossi
authors.forename: Francesco
authors.initials: F
authors.lastname: Zerbetto
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D002627:Chemistry, Physical / Q000379:methods*; D006860:Hydrogen Bonding; D008956:Models, Chemical; D015233:Models, Statistical; D016012:Poisson Distribution; D011336:Probability; D011392:Proline / Q000737:chemistry; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D011506:Proteins; D011392:Proline