Contribution of long-range interactions to the secondary structure of an unfolded globin.
This work explores the effect of long-range tertiary contacts on the distribution of residual secondary structure in the unfolded state of an alpha-helical protein. N-terminal fragments of increasing length, in conjunction with multidimensional nuclear magnetic resonance, were employed. A protein representative of the ubiquitous globin fold was chosen as the model system. We found that, while most of the detectable alpha-helical population in the unfolded ensemble does not depend on the presence of the C-terminal region (corresponding to the native G and H helices), specific N-to-C long-range contacts between the H and A-B-C regions enhance the helical secondary structure content of the N terminus (A-B-C regions). The simple approach introduced here, based on the evaluation of N-terminal polypeptide fragments of increasing length, is of general applicability to identify the influence of long-range interactions in unfolded proteins.
Fedyukina
Daria V
DV
Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Rajagopalan
Senapathy
S
Sekhar
Ashok
A
Fulmer
Eric C
EC
Eun
Ye-Jin
YJ
Cavagnero
Silvia
S
D000818:Animals; D001059:Apoproteins / Q000737:chemistry / Q000378:metabolism; D005914:Globins / Q000737:chemistry* / Q000378:metabolism*; D009211:Myoglobin / Q000737:chemistry / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D017433:Protein Structure, Secondary; D058767:Protein Unfolding
D001059:Apoproteins; D009211:Myoglobin; C010857:apomyoglobin; D005914:Globins
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