User:Eric Martz/Ramachandran Principle Quiz

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→	The phi dihedral (torsion) angle is defined by (1) the carboxy carbon from the previous amino acid; (2) N in the amino acid containing the phi bond; (3) C_α in the amino acid containing the phi bond; and (4) the carboxy carbon of the amino acid containing the phi bond.

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→	The phi angle involves the carboxy carbon of the previous amino acid in a polypeptide chain. The psi angle involves the N of the subsequent amino acid. Therefore an isolated single amino acid has neither phi nor psi angles.

Primary structure.

Secondary structure.

Tertiary structure.

Quaternary structure.

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All possible phi-psi angle combinations.

A limited range of phi-psi angle combinations.

A limited range of phi angles with all possible psi angles.

A limited range of psi angles with all possible phi angles.

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	They optimize main-chain hydrogen bonds.
	They represent all possible conformations.
	They maximize clashes between atoms.
	They minimize clashes between atoms.

	Between two non-bonded atoms is called a clash.
	Between two covalently bonded atoms is called a clash.
	Occurring between two non-bonded atoms in a molecular model signifies an energetically favorable interaction.
	Is physically impossible between two non-bonded real atoms.

	Where clashes occur.
	Where clashes do not occur.
	Where alpha helices occur.
	Where beta strands occur.
	Where neither alpha helices nor beta strands occur.
	Where the phi and psi angles are energetically favorable.

@@ Line 48: / Line 48: @@
 - A limited range of phi angles with all possible psi angles.
 - A limited range of psi angles with all possible phi angles.
-||See [[Protein primary, secondary, tertiary and quaternary structure]].
+||See [http://bioinformatics.org/molvis/phipsi/index.htm#plot Ramachandran Plot].
 {Common secondary structures are energetically favored because

Revision as of 23:50, 23 June 2018