Risk which is common to an entire class of assets or liabilities. The value of investments may decline over a given time period simply because of economic changes or other events that impact large portions of the market.
Properties of the alpha-helix. 1  The structure repeats itself every 5.4 Angstroms along the helix axis, ie we say that the alpha-helix has a pitch of 5.4 Angstroms. Alpha-helices have 3.6 amino acid residues per turn, ie a helix 36 amino acids long would form 10 turns.
Similar structures include the 310 helix (hydrogen bonding) and the Ï-helix (hydrogen bonding). The Î± helix can be described as a 3.6 13 helix, since the i + 4 spacing adds 3 more atoms to the H-bonded loop compared to the tighter 3 10 helix, and on average, 3.6 amino acids are involved in one ring of Î± helix.