helix

In an alpha-helix, the protein chain is coiled like a loosely-coiled spring.

The available X-ray crystallographic structure of PA complex with PB1 N-terminal fragment (amino acids 1-15) shows that, when bound to PA1, the secondary structure of 115 N-terminal fragment of PB1 is an alpha-helix [5].

In the Style/Edit Global Style menu, uncheck "alpha-helix"; the cylinders disappear.

There are two types of arrangement for secondary structures: the alpha-helix and beta sheets.

In one case, that of a glucocorticoid receptor protein, they found a specific spiral structure -- an alpha-helix -- that appears to spur transcription.

Studying the configuration of how calpastatin bound to the active site of the calpain complex, "we found that there was a small alpha-helix that fit into the active site of the calpain enzyme," Greenbaum said.

Whereas a single alpha-helix consists of an elegant spiral of 15 to 20 amino acids, the beta sheet requires 60 to 70 amino acids.