Metal Ions Questions

1995

No questions.

1996

"Discuss, with diagrams, how proteins and their prosthetic groups provide
binding sites to allow individual metal ions to perform specific
functions."

"Figure 2a shows a representation of a regulatory protein [calmodulin]
that transduces intracellular signals in response to changes in
concentrations of a divalent metal ion.

(a)	Name the molecule and the class of proteins to which it belongs.
(b)	The protein binds four divalent metal ions.  Say which ion is usually
	bound with high affinity to the protein.  Indicate the position of the ion
	binding sites on the figure and describe the nature of the functional
	groups which are likely to coordinate to the ions.
(c)	Other divalent ions can also bind to the protein, with much lower
	affinity.  What are the chemical differences between the usual ion and
	other ions found bound to this protein which are likely to contribute to
	this difference in affinity?
(d)	How would you experimentally determine the binding affinity of the
	ions for such a protein?
(e)	The protein is able to bind to a variety of intracellular targets in
	response to high-affinity ion binding.  Figure 2b shows the structure of a
	complex of the protein and a peptide from a target protein.  Describe the
	overall conformational change that occurs in the protein as a result of
	binding to the target peptide.
(f)	What is the structural basis for the modulation of the activity of the
	target proteins by the regulatory protein?  Suggest structural mechanisms
	that explain the ability of the regulatory protein to bind to numerous and
	diverse targets.

1997

"Describe the different biological roles played by zinc and copper in the
context of their different chemical properties."

1998

" 'Mg2+ and Zn2+ have some properties in common, but their differences
determine their distinctive biological roles.'  Discuss."

1999

" 'Biology exploits the properties of many metal ions to achieve a range
of functions.'  Illustrate this statement with references to the
biological roles of Mn, Mo, Co, Ni, and Cu."

2000

"How do K+ and Ca2+ bind to proteins?  Discuss how such binding is related
to the biological functions of these ions."