Indicate whether each of the following descriptions better applies to the determination of atomic structure of proteins by x-ray diffraction (X) or by nuclear magnetic resonance (NMR) spectroscopy (N). Your answer would be a five-letter string composed of letters X and N only, e.g. NNXNN.
( ) It is more suitable for complexes larger than about 100 kD.
( ) It requires samples to crystallize.
( ) It can better reveal dynamics of molecular motions.
( ) It involves the calculation of electron-density maps.
( ) It is used to determine the solution structure of proteins.

Question

Indicate whether each of the following descriptions better applies to the determination of atomic structure of proteins by x-ray diffraction (X) or by nuclear magnetic resonance (NMR) spectroscopy (N). Your answer would be a five-letter string composed of letters X and N only, e.g. NNXNN.
( )	It is more suitable for complexes larger than about 100 kD.
( )	It requires samples to crystallize.
( )	It can better reveal dynamics of molecular motions.
( )	It involves the calculation of electron-density maps.
( )	It is used to determine the solution structure of proteins.

Quizplus · Accepted Answer

Each method has advantages and disadvantages. For instance, NMR has the advantage of providing information about the conformation of proteins in solution and the dynamic changes in their structure. It also requires the preparation of relatively small quantities of the protein of interest. However, for technical reasons, its use is currently limited to molecules smaller than 100,000 daltons.

Indicate Whether Each of the Following Descriptions Better Applies to the Determination