PMC:2728203 / 13933-15268 JSONTXT

{"target":"https://pubannotation.org/docs/sourcedb/PMC/sourceid/2728203","sourcedb":"PMC","sourceid":"2728203","source_url":"https://www.ncbi.nlm.nih.gov/pmc/2728203","text":"As illustrated in Fig. 2b, the solution structure of the N-terminal domain of Nab2 was based on a bundle of five α-helices (H1–H5). Unlike the highly compact bundle formed by helices H1–H4, each of which made multiple contacts with at least two of the other helices, helix H5 was less tightly associated with the rest of the structure. The only NOE constraints from helix H5 to other parts of the structure were all contacts to helix H1 (Ala84 contacts Asn9, Val12, and Ile13; Ile87 contacts Ile13 and Glu16; Ile91 contacts Glu16 and Ala19; Asn95 contacts Ala19 and Gly20). These contacts were sufficient to constrain the position of helix H5 with comparable precision to those of the other helices, but they were much fewer in number than the constraints involving any of the other helices. Further evidence for the relatively loose attachment of helix H5 to the rest of the structure came from the observation that NMR samples were slowly proteolyzed from the C-terminus. Over a period of several weeks, many signals assigned to residues of helix H5 were progressively lost from the spectra, whereas the signals assigned to helices H1–H4 were largely unaffected. The signals for protons in helix H5 were generally weaker than other components of the structure and decreased with time, consistent with its being gradually proteolyzed.","tracks":[]}