Novel protein structural motifs containing two-turn and longer 3(10)-helices.
The 3(10)-helix constitutes a small but significant fraction of secondary structural elements in proteins. Protein data base surveys have shown these helices to be present as alpha-helical extensions, in loops and as connectors between beta-strands. The present work focuses on two-turn and longer 3(10)-helices where we establish that two-turn and longer 3(10) helices, unlike the more abundant single-turn 3(10)-helices, frequently occur independent of any other contiguous secondary structural elements. More importantly, a large fraction of these independent two-turn and longer 3(10)-helices, along with alpha-helices and beta-strands, are found to form novel super-secondary structural motifs in several proteins with possible implications for protein folding, local conformational relaxation and biological functions.
Pal
L
L
Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VIIM, Calcutta 700 054, India.
Basu
G
G
D020816:Amino Acid Motifs; D000596:Amino Acids / Q000737:chemistry; D016208:Databases, Factual; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry*; D013329:Structure-Activity Relationship
D000596:Amino Acids; D011506:Proteins