Which protein characteristics are primarily assessed through circular dichroism spectroscopy?

Circular dichroism (CD) spectroscopy is a powerful analytical technique used to study the secondary structure and conformational changes of proteins. This method relies on the differential absorption of circularly polarized light, which allows researchers to determine the content and arrangement of secondary structural elements such as alpha helices and beta sheets in proteins.

When proteins fold into their native structures, they adopt specific secondary motifs that have characteristic CD spectra. By analyzing the CD spectrum, scientists can assess the proportion of these structural features, providing insights into the protein's folding state and overall structural integrity. This makes CD spectroscopy particularly valuable for evaluating protein folding and stability under various conditions, as well as monitoring conformational changes during processes such as ligand binding or denaturation.

The other characteristics listed do not align with the primary outputs of circular dichroism spectroscopy. The primary structure refers to the linear sequence of amino acids in a protein and cannot be directly determined by CD. Molecular weight is typically assessed using techniques like mass spectrometry or gel filtration, while solubility and hydrophobicity are more suited to methods like chromatography or precipitation assays. Lastly, amino acid composition analysis is generally performed using techniques such as amino acid analysis or sequencing rather than CD spectroscopy. Thus, the correct choice highlights the ability of