Is there a Möbius band in closed protein beta-sheets?
Protein beta-strands can form beta-barrels and other complicated structures. This paper defines bifurcations and pseudobifurcations of beta-sheets. They are important structural elements for protein folding. This paper also presents a characteristic number that can be used to test whether the surface of a closed beta-sheet is one- or two-sided. Searching the whole Protein Data Bank released in April 1997 with the definition of beta-structures given by the DSSP program, we do not find any one-sided beta-Möbius band. However, there are interesting structures such as beta-bands with odd number of antiparallel ladders and odd number of bifurcations. There are also beta-structures that are closed only at a singular point. Adding a small patch near the singular point in different ways can make it a one- or two-sided surface. The catalytic triad of a GMP synthetase (1GPM) is near the singular point of such a beta-sheet.
Liu
W M
WM
Department of Computer and Information Science, Indiana University, Indianapolis 46202-5132, USA.
D017100:Bacteriophage P22 / Q000737:chemistry; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002772:Cholera Toxin / Q000737:chemistry; D006026:Glycoside Hydrolases / Q000737:chemistry; D006860:Hydrogen Bonding; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012984:Software; D017376:Viral Tail Proteins / Q000737:chemistry; D010566:Virulence Factors, Bordetella / Q000737:chemistry
D017376:Viral Tail Proteins; D010566:Virulence Factors, Bordetella; D002772:Cholera Toxin; D006026:Glycoside Hydrolases; C083268:tailspike protein, bacteriophage