Self‐complementary motifs (SCM) in α‐crystallin small heat shock proteins

Farnsworth, Patricia N.; Singh, Kamalendra

doi:10.1016/s0014-5793(00)02051-2

Cited by 13 publications

(7 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The crystal structure indicates that this loop is surface exposed and therefore well suited for protein-protein interactions (155). Several residues in this loop are involved in intersubunit contacts (79,155). Likewise, in wheat Hsp16.9, several oligomerization interfaces coincide with putative substrate-binding sites, which led to the proposal that heat-induced chaperone activity is triggered by dissociation of the ␣-Hsp complex (338a).…”

Section: Substrate-binding Sitesmentioning

confidence: 99%

α-Crystallin-Type Heat Shock Proteins: Socializing Minichaperones in the Context of a Multichaperone Network

Narberhaus

2002

Microbiol Mol Biol Rev

497

415

View full text Add to dashboard Cite

SUMMARY α-Crystallins were originally recognized as proteins contributing to the transparency of the mammalian eye lens. Subsequently, they have been found in many, but not all, members of the Archaea, Bacteria, and Eucarya. Most members of the diverse α-crystallin family have four common structural and functional features: (i) a small monomeric molecular mass between 12 and 43 kDa; (ii) the formation of large oligomeric complexes; (iii) the presence of a moderately conserved central region, the so-called α-crystallin domain; and (iv) molecular chaperone activity. Since α-crystallins are induced by a temperature upshift in many organisms, they are often referred to as small heat shock proteins (sHsps) or, more accurately, α-Hsps. α-Crystallins are integrated into a highly flexible and synergistic multichaperone network evolved to secure protein quality control in the cell. Their chaperone activity is limited to the binding of unfolding intermediates in order to protect them from irreversible aggregation. Productive release and refolding of captured proteins into the native state requires close cooperation with other cellular chaperones. In addition, α-Hsps seem to play an important role in membrane stabilization. The review compiles information on the abundance, sequence conservation, regulation, structure, and function of α-Hsps with an emphasis on the microbial members of this chaperone family.

show abstract

Section: Substrate-binding Sitesmentioning

confidence: 99%

α-Crystallin-Type Heat Shock Proteins: Socializing Minichaperones in the Context of a Multichaperone Network

Narberhaus

2002

Microbiol Mol Biol Rev

497

415

View full text Add to dashboard Cite

show abstract

“…Some of their general roles might be regarded as complementary to the cascade of events starting from transcription of mRNA resulting in the production of functioning proteins. Small HSPs have been shown to include within their sequences some ''crowded'' charged amino acids (51). Another example is the murine HSP86, which was found to contain internal peptide repeats of Glu-Lys-Glu within a region of highly charged amino acid residues (52).…”

Section: The Ag% Content Within Exons Of the Mrnas Of Hsps Of Five Eumentioning

confidence: 99%

Adaptive role of increased frequency of polypurine tracts in mRNA sequences of thermophilic prokaryotes

Paz¹,

Mester²,

Baca³

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The mechanism of an organism's adaptation to high temperatures has been investigated intensively in recent years. It was suggested that the macromolecules of thermophilic microorganisms (especially proteins) have structural features that enhance their thermostability. We compared mRNA sequences of 72 fully sequenced prokaryotic proteomes (14 thermophilic and 58 mesophilic species). Although the differences between the percentage of adenine plus guanine content of whole mRNAs of different prokaryotic species are much lower than those of guanine plus cytosine content, the thermophile purinepyrimidine (R/Y) ratio within their mRNAs is significantly higher than that of the mesophiles. The first and third codon positions of both thermophiles and mesophiles are purine-biased, with the bias more pronounced by the thermophiles. Thermophile mRNAs that display the highest R/Y ratio (1.43-1.69) are those of the ribosomal proteins, histone-like proteins, DNA-dependent RNA polymerase subunits, and heat-shock proteins. Within mesophilic prokaryotes and five eukaryotic species, the R/Y ratio of the mRNAs of heat-shock proteins is higher than their average over coding part of the genome. Polypurine tracts (R) n (with n > 5) are much more abundant within the thermophile mRNAs compared with mesophiles. Between two sequential pure-purinic codons of thermophile mRNAs, there is a rather strong tendency for the occurrence of adenine but not guanine tracts. The data suggest that mixed adenine⅐guanine and polyadenine tracts in mRNAs increase the thermostability beyond the contribution of amino acids encoded by purine tracts, which highlights the importance of ecological stress in the evolution of genome architecture.A daptive strategies of organisms to extreme environments such as exceptional salinity, high pressure, nonphysiological pH, anaerobic conditions, and high and low temperatures are of primary importance for evolutionary studies (1). Revealing and understanding the special features of the macromolecules of thermophilic prokaryotes with high to very high optimum growth temperatures (OGTs) (50-113°C), compared with much lower ranges (20-37°C) of prokaryotic mesophiles, is of particular interest. Historically, investigators first were interested in revealing the unique features of the thermophile proteins that contribute to their thermostability (2, 3). Clarifying the principles of enhanced thermostability is important theoretically and practically. Deciphering improved enzymes with higher thermostability is of significant economic value to some industries. In this study, our aim was to unravel differences between mRNAs and the proteins of thermophiles and mesophiles to identify common features of the thermophiles' molecules that might contribute to thermostability. We restricted this study to the protein-coding transcripts. Understanding how the adaptation of the transcription and translation machinery (and products) to high temperature is achieved is central to both theoretical models and in vitro experimentation. Therefore, b...

show abstract

“…The SI peptide is comprised of an ionic, self-complementary motif (iSCM). This motif was first identified in small heat shock proteins, crystalline oligomeric complexes [7], and in peptides with labile secondary structures [2]. The interaction between these polypeptides occurs at a site where antiparallel-oriented iSCMs monomers (on opposing polypeptides) interact.…”

Section: Introductionmentioning

confidence: 96%

Triazavirine supramolecular complexes as modifiers of the peptide oligomeric structure

Швецов

Zabrodskaya

Nekrasov

et al. 2017

Preprint

View full text Add to dashboard Cite

In this study we present molecular dynamics simulations of the antiviral drug triazavirine, that affects formation of amyloid-like fibrils of the model peptide (SI). According to our simulations, triazavirine is able to form linear supramolecular structures which can act as shields and prevent interactions between SI monomers. This model, as validated by simulations, provides an adequate explanation of triazavirine's mechanism of action as it pertains to SI peptide fibril formation.

show abstract

Self‐complementary motifs (SCM) in α‐crystallin small heat shock proteins

Cited by 13 publications

References 30 publications

α-Crystallin-Type Heat Shock Proteins: Socializing Minichaperones in the Context of a Multichaperone Network

α-Crystallin-Type Heat Shock Proteins: Socializing Minichaperones in the Context of a Multichaperone Network

Adaptive role of increased frequency of polypurine tracts in mRNA sequences of thermophilic prokaryotes

Triazavirine supramolecular complexes as modifiers of the peptide oligomeric structure

Contact Info

Product

Resources

About