2017  0,977
2016  0,799
2015  0,662
2014  0,740
2013  0,739
2012  0,637
2011  0,658
2010  0,654
2009  0,570
2008  0,849
2007  0,805
2006  0,330
2005  0,435
2004  0,623
2003  0,567
2002  0,641
2001  0,490
2000  0,477
1999  0,762
1998  0,785
1997  0,507
1996  0,518
1995  0,502
Vol 52(2018) N 1 p. 36-41; DOI 10.1134/S0026893318010077 Full Text

A.M. Kargatov, A.V. Efimov*

Unique Combinations of βαβ-Units and Π-Like Modules in Proteins and Specific Features of Their Amino Acid Sequences

Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow oblast, 142290 Russia

Received - 2017-05-11; Accepted - 2017-06-19

Possible combinations of βαβ-units and Π-like modules in proteins in both right- and left-handed forms have been analyzed in detail. The correlation between the mutual arrangement of the structural elements in the polypeptide chain and their handedness has been shown. In the βαβП combinations, which is encountered most frequently in proteins, the П-module follows the βαβ unit along the chain and both elements are right-handed. In the Пβαβ combinations, where the П-module is located at the N end and the βαβ-unit follows it, the former is left-handed and the latter is right-handed. In relatively rare combinations of the left-handed βαβ-units and right-handed П-modules, the βαβ-unit follows П-module in the chain. The combinations of left-handed П-modules and the left-handed βαβ-units are unobservable in proteins. It has also been shown that the П-modules with a β-strand-α-helix-arch-β-strand structure are observed in proteins only in a right-handed form and half of them (51%) contains cis-prolines in their arches. These arches of nonhomologous proteins, as well as the positions of cis-prolines, nearly coincide when superimposed. The superimposed П-modules also demonstrate that their overall folds are very similar. Structural alignment of their amino acid sequences has shown that the П-modules have very similar sequence patterns of the key hydrophobic, hydrophilic, glycine, and cis-proline residues.

α-helix, β-strand, crossover loop, arch, structural motif, cis-proline