Protein structures in SDS micelle-protein complexes

Parker, William; Song, Pill‐Soon

doi:10.1016/s0006-3495(92)81949-5

Cited by 139 publications

(98 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This study reported a decrease in dichroism at 222 nm that was attributed to an increase in the ␣-helix content, but our data indicate that such a change may not be indicative of an increase in ␣-helix. In any case, if it does represent an increase in ␣-helical content, there is no reason to expect it to be a specific effect since even SDS micelles can increase the helix content of proteins (58,71), and no biological or biochemical role for phosphoinositide binding to ActA has been demonstrated.…”

Section: Discussionmentioning

confidence: 99%

“…In general, proteins bind to SDS with a fairly constant ratio of 1.4 g of SDS/g of protein (57). However, this binding is mostly hydrophobic in nature (57) and can even result in an increase in secondary structure especially in amphiphilic regions (54,58). It would not be surprising that natively unfolded proteins, being very extended and hydrophilic, do not form compact helices with SDS micelles and, therefore, migrate with a low relative mobility on SDS-PAGE.…”

Section: Characterization Of the Soluble Acta Protein And Syntheticmentioning

confidence: 99%

See 1 more Smart Citation

Close Packing of Listeria monocytogenes ActA, a Natively Unfolded Protein, Enhances F-actin Assembly without Dimerization

Footer

Lyo

Theriot

2008

Journal of Biological Chemistry

View full text Add to dashboard Cite

Studies of the biochemistry of Listeria monocytogenes virulence protein ActA have typically focused on the behavior of bacteria in complex systems or on the characterization of the protein after expression and purification. Although prior in vivo work has proposed that ActA forms dimers on the surface of L. monocytogenes, dimerization has not been demonstrated in vitro, and little consideration has been given to the surface environment where ActA performs its pivotal role in bacterial actinbased motility. We have synthesized and characterized an ActA dimer and provide evidence that the two ActA molecules do not interact with each other even when tethered together. However, we also demonstrate that artificial dimers provide superior activation of actin nucleation by the Arp2/3 complex compared with monomers and that increased activation of the Arp2/3 complex by dimers may be a general property of Arp2/3 activators. It appears that the close packing (ϳ19 nm) of ActA molecules on the surface of L. monocytogenes is so dense that the kinetics of actin nucleation mimic that of synthetic ActA dimers. We also present observations indicating that ActA is a natively unfolded protein, largely random coil that is responsible for many of the unique physical properties of ActA including its extended structure, aberrant mobility during SDS-PAGE, and ability to resist irreversible denaturation upon heating.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Characterization Of the Soluble Acta Protein And Syntheticmentioning

confidence: 99%

Close Packing of Listeria monocytogenes ActA, a Natively Unfolded Protein, Enhances F-actin Assembly without Dimerization

Footer

Lyo

Theriot

2008

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…Within the N-terminal 54 amino acid chain, there are eight pairs of charged residues in both oat and pea phyA spaced seven residues apart, roughly two turns of an a-helix. Micelle-induced helical folding of the 54-mer showed that this peptide possesses high amphiphilicity (Parker & Song 1992;Wells 1996).…”

Section: Light-induced Conformational Changesmentioning

confidence: 99%

Chromophore: apoprotein interactions in phytochrome A*

Song

Park

Furuya

1997

Plant Cell & Environment

View full text Add to dashboard Cite

Pbytocbromes are molecular ligbt switcbes by virtue of their pbotocbromic red/far-red reversibility. The His-324 residue next to the chromophore-Iinked Cys-323 plays a critical role in conferring photochromism to the tetrapyrrole chromophore in native phytochrome A. The chromophore appears to be enclosed between the amphiphilic a-helical chains in a hydrophobie pocket. The absorbance maxima of both the Pr and the Pfr forms of pea phytochrome A are blue-shifted by 10 and 20 nm, respectively, upon C-terminal truncation. We speculate that the quaternary structure of the phytochrome A molecule involves some interactions of the C-terminal half with the chromophore domain. The Pfr conformation of phytochrome includes an amphiphilic ahelix of the amino terminal chain, which occurs in 113 ms after picosecond photoisomerization of the Pr form. Compared to a-helical folding, unfolding of the a-helix occurs faster in about 310 fis upon phototransformation of the Pfr form of phytochrome A. The photochromic transformation of phytochrome A modulates protein kinase-catalysed phosphorylation sites in vivo and in vitro, but only a subtle local change in conformation is detectable in the phosphorylated phytochromes. This suggests that the post-transiational modification serves as a surface label, rather than a transducer-activating trigger, for the recognition of a putative phytochrome receptor.

show abstract

“…Sodium decyl sulfate, which has a hydrophobic tail and hydrophilic head, may form stable nano micelles in aqueous solution when its concentration is above CMC concentration. Because of the shorter chain length, the formed sodium decyl sulfate micelles have smaller diameter, stronger hydrophobic interaction and electrostatic effect [3][4][5][6], which may provide a hydrophobic environment and enhance the stability and activity of an artificial peroxidase [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%