Zn(2+)-mediated structure formation and compaction of the "natively unfolded" human prothymosin alpha.
Human recombinant prothymosin alpha (ProTalpha) is known to have coil-like conformation at neutral pH; i.e., it belongs to the class of "natively unfolded" proteins. By means of circular dichroism, SAXS, and ANS fluorescence, we have investigated the effect of several divalent cations on the structure of this protein. Results of these studies are consistent with the conclusion that ProTalpha conformation is unaffected by large excess of Ca(2+), Mg(2+), Mn(2+), Cu(2+), and Ni(2+). However, Zn(2+) induces compaction and considerable rearrangement of the protein structure. This means that ProTalpha can specifically interact with Zn(2+) (K(D) approximately 10(-3) M), and such interactions induce folding of the natively unfolded protein into a compact partially folded (premolten globule-like) conformation. It is possible that these structural changes may be important for the function of this protein.
Uversky
V N
VN
Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow Region, 142292, Russia. uversky@hydrogen.ucsc.edu
Gillespie
J R
JR
Millett
I S
IS
Khodyakova
A V
AV
Vasilenko
R N
RN
Vasiliev
A M
AM
Rodionov
I L
IL
Kozlovskaya
G D
GD
Dolgikh
D A
DA
Fink
A L
AL
Doniach
S
S
Permyakov
E A
EA
Abramov
V M
VM
D000595:Amino Acid Sequence; D001665:Binding Sites; D002413:Cations, Divalent / Q000494:pharmacology; D002942:Circular Dichroism; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics; D011487:Protein Conformation / Q000187:drug effects; D017510:Protein Folding; D011498:Protein Precursors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012542:Scattering, Radiation; D017386:Sequence Homology, Amino Acid; D013050:Spectrometry, Fluorescence; D013947:Thymosin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015032:Zinc / Q000378:metabolism / Q000494:pharmacology
D002413:Cations, Divalent; D010446:Peptide Fragments; D011498:Protein Precursors; D011994:Recombinant Proteins; C040782:prothymosin alpha; D013947:Thymosin; D015032:Zinc