Ligand-dependent structural changes and limited proteolysis of Escherichia coli phosphofructokinase-2

2002 ◽  
Vol 406 (2) ◽  
pp. 289-295 ◽  
Author(s):  
Ricardo Cabrera ◽  
Victoria Guixé ◽  
Jennifer Alfaro ◽  
Patricio H Rodrı́guez ◽  
Jorge Babul
Keyword(s):  
Escherichia Coli ◽  
Structural Changes ◽  
Limited Proteolysis

Structural changes in 16S RNA from Escherichia coli upon unfolding by urea

Biopolymers ◽  
1993 ◽  
Vol 33 (11) ◽  
pp. 1747-1755 ◽  
Author(s):  
A. A. Timchenko ◽  
J. Langowski ◽  
I. N. Serdyuk
Keyword(s):  
Escherichia Coli ◽  
Structural Changes ◽  
16S Rna

Conformational Alterations of α2-Antiplasmin Induced by Complex Formation with Plasmin

1979 ◽  
Author(s):  
E.F. Plow ◽  
B. Wiman ◽  
D. Collen
Keyword(s):  
Complex Formation ◽  
Structural Changes ◽  
Limited Proteolysis ◽  
Terminal Region ◽  
The Other ◽  
Antigenic Determinants ◽  
Chemical Analyses ◽  
Large Fragment ◽  
Reactive Site ◽  
Immunodiffusion Analysis

The conformational and structural changes induced in the α2-antiplasmin (AP) molecule by complex formation with plasmin have been analyzed utilizing quantitative radioimmuno-chemical analyses. Complexes prepared in plasmin excess -(PAP-P) and therefore subjected to limited proteolysis and complexes prepared in AP excess (PAP-A) have been compared with free AP. With AP antiserum, PAP-A, PAP-P and AP yielded reactions of complete identity by immunodiffusion analysis. In radioimmunoassay, however, these were clearly distinguished, and four distinct sets of antigenic determinants were delineated. Set I determinants were expressed equivalently by PAP-P, PAP-A and AP and were, therefore, not altered by complex formation. This set was recognized by 90% of the antibodies, and the determinants were all included within a large fragment of Mr 60,000 derived from the NH2-terminal region of AP. The other three sets of determinants were modulated by complex formation. Set II was expressed by PAP-A and AP but not by PAP-P, and these were sensitive to proteolysis by plasmin. Set III determinants were expressed only by AP and were localized to a peptide of Mr 8,000 derived from the COOH-terminal region of AP. Set IV determinants were also present only on AP but were not present in the peptide and required an intact reactive site in AP for expression. Thus, there is evidence for multiple conformational modulations in AP induced by complex formation, and these modulations can be pinpointed to specific loci within the AP molecule.

scholarly journals The Dimerization Function of MinC Resides in a Structurally Autonomous C-Terminal Domain

2001 ◽  
Vol 183 (22) ◽  
pp. 6684-6687 ◽  
Author(s):  
Tim H. Szeto ◽  
Susan L. Rowland ◽  
Glenn F. King
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Limited Proteolysis ◽  
Terminal Domain ◽  
Cell Division Inhibitor

ABSTRACT Limited proteolysis of the Escherichia coli cell division inhibitor MinC reveals that its dimerization function resides in a structurally autonomous C-terminal domain. We show that cytoplasmic MinC is poised near the monomer-dimer equilibrium and propose that it only becomes entirely dimeric once recruited to the membrane by MinD.

scholarly journals Functional domain organization of the potato α-glucan, water dikinase (GWD): evidence for separate site catalysis as revealed by limited proteolysis and deletion mutants

2005 ◽  
Vol 385 (2) ◽  
pp. 355-361 ◽  
Author(s):  
René MIKKELSEN ◽  
Andreas BLENNOW
Keyword(s):  
Structural Changes ◽  
Sequence Similarity ◽  
Limited Proteolysis ◽  
Phosphoryl Group ◽  
Deletion Mutants ◽  
Functional Domain ◽  
Partial Reaction ◽  
Atp Binding Site ◽  
Binding Domains ◽  
Terminal Domains

The potato tuber (Solanum tuberosum) GWD (α-glucan, water dikinase) catalyses the phosphorylation of starch by a dikinase-type reaction mechanism in which the β-phosphate of ATP is transferred to the glucosyl residue of amylopectin. GWD shows sequence similarity to bacterial pyruvate, water dikinase and PPDK (pyruvate, phosphate dikinase). In the present study, we examine the structure–function relationship of GWD. Analysis of proteolytic fragments of GWD, in conjunction with peptide microsequencing and the generation of deletion mutants, indicates that GWD is comprised of five discrete domains of 37, 24, 21, 36 and 38 kDa. The catalytic histidine, which mediates the phosphoryl group transfer from ATP to starch, is located on the 36 kDa fragment, whereas the 38 kDa C-terminal fragment contains the ATP-binding site. Binding of the glucan molecule appears to be confined to regions containing the three N-terminal domains. Deletion mutants were generated to investigate the functional interdependency of the putative ATP- and glucan-binding domains. A truncated form of GWD expressing the 36 and 38 kDa C-terminal domains was found to catalyse the E+ATP→E-P+AMP+Pi (where Pi stands for orthophosphate) partial reaction, but not the E-P+glucan→E+glucan-P partial reaction. CD experiments provided evidence for large structural changes on autophosphorylation of GWD, indicating that GWD employs a swivelling-domain mechanism for enzymic phosphotransfer similar to that seen for PPDK.

scholarly journals Consequences of poly-glutamine repeat length for the conformation and folding of the androgen receptor amino-terminal domain

2008 ◽  
Vol 41 (5) ◽  
pp. 301-314 ◽  
Author(s):  
Philippa Davies ◽  
Kate Watt ◽  
Sharon M Kelly ◽  
Caroline Clark ◽  
Nicholas C Price ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Structural Changes ◽  
Muscular Atrophy ◽  
Cell Signalling ◽  
Limited Proteolysis ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Helix Structure ◽  
Α Helix ◽  
Amino Terminal Domain

Poly-amino acid repeats, especially long stretches of glutamine (Q), are common features of transcription factors and cell-signalling proteins and are prone to expansion, resulting in neurodegenerative diseases. The amino-terminal domain of the androgen receptor (AR-NTD) has a poly-Q repeat between 9 and 36 residues, which when it expands above 40 residues results in spinal bulbar muscular atrophy. We have used spectroscopy and biochemical analysis to investigate the structural consequences of an expanded repeat (Q45) or removal of the repeat (ΔQ) on the folding of the AR-NTD. Circular dichroism spectroscopy revealed that in aqueous solution, the AR-NTD has a relatively limited amount of stable secondary structure. Expansion of the poly-Q repeat resulted in a modest increase in α-helix structure, while deletion of the repeat resulted in a small loss of α-helix structure. These effects were more pronounced in the presence of the structure-promoting solvent trifluoroethanol or the natural osmolyte trimethylamine N-oxide. Fluorescence spectroscopy showed that the microenvironments of four tryptophan residues were also altered after the deletion of the Q stretch. Other structural changes were observed for the AR-NTDQ45 polypeptide after limited proteolysis; in addition, this polypeptide not only showed enhanced binding of the hydrophobic probe 8-anilinonaphthalene-1-sulphonic acid but was more sensitive to urea-induced unfolding. Taken together, these findings support the view that the presence and length of the poly-Q repeat modulate the folding and structure of the AR-NTD.

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