A proton nuclear magnetic resonance assignment and secondary structure determination of recombinant human thioredoxin

Biochemistry. 1989 Aug 22;28(17):7088-97. doi: 10.1021/bi00443a045.


Two-dimensional 1H NMR spectroscopy has been applied to a structural analysis of the reduced form of a recombinant human thioredoxin, a ubiquitous dithiol oxidoreductase recently isolated from an immunocompetent lymphoblastoid cell line. The sequential assignment of the spectrum, including all proline residues, has been accomplished by using experiments to demonstrate through-bond and through-space connectivities. The secondary structure has been determined by a qualitative interpretation of nuclear Overhauser effects, NH exchange data, and 3JHN alpha coupling constants. The secondary structure was found to be similar to that of the X-ray structure of Escherichia coli thioredoxin, consisting of a mixed five-stranded beta-sheet surrounded by four alpha-helices. The assignment and structural characterization of human thioredoxin was facilitated by the increased resolution and sensitivity afforded by a magnetic field strength of 600 MHz and required the use of two temperatures and two pH conditions to resolve ambiguities caused by a duplication of resonances. This duplication, extending from Phe-41 to Val-59, and including Lys-3-Ile-5, Val-24, Val-25, Asn-39, and Ile-101-Glu-103, appears to be due to heterogeneity arising from the presence or absence of the N-terminal methionine.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins* / genetics
  • Escherichia coli / genetics
  • Humans
  • Magnetic Resonance Spectroscopy / methods
  • Molecular Sequence Data
  • Oxidation-Reduction
  • Protein Conformation
  • Recombinant Proteins
  • Software
  • Thioredoxins* / genetics


  • Bacterial Proteins
  • Recombinant Proteins
  • Thioredoxins