Cotranslational Folding of Globin

Komar, Anton A.; Kommer, Aigar; Krasheninnikov, Igor A.; Spirin, Alexander S.

doi:10.1074/jbc.272.16.10646

Cited by 142 publications

(95 citation statements)

References 57 publications

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“…Given that a helices and other structural features are capable of forming spontaneously in less than a few microseconds (30,36,41,111), it is plausible that a and b chains could acquire some of their secondary and tertiary structure co-translationally. Several studies using cell-free protein expression systems support this idea and suggest that heme or hemin insertion is also a co-translational process (65,66,95). Heme uptake causes helicity increases from 18% to 65% in a chains and 51-65% in b chains (107 figure. Not depicted is the possibility that heme insertion into one chain drives subunit assembly and subsequent heme insertion into another.…”

Section: Pathways For Hemoglobin Assembly In Vivo and In Vitromentioning

confidence: 77%

The Role of Alpha-Hemoglobin Stabilizing Protein in Redox Chemistry, Denaturation, and Hemoglobin Assembly

Mollan

Weiss

et al. 2010

Antioxidants & Redox Signaling

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Hemoglobin biosynthesis in erythrocyte precursors involves several steps. The correct ratios and concentrations of normal alpha (a) and beta (b) globin proteins must be expressed; apoproteins must be folded correctly; heme must be synthesized and incorporated into these globins rapidly; and the individual a and b subunits must be rapidly and correctly assembled into heterotetramers. These events occur on a large scale in vivo, and dysregulation causes serious clinical disorders such as thalassemia syndromes. Recent work has implicated a conserved erythroid protein known as Alpha-Hemoglobin Stabilizing Protein (AHSP) as a participant in these events. Current evidence suggests that AHSP enhances a subunit stability and diminishes its participation in harmful redox chemistry. There is also evidence that AHSP facilitates one or more early-stage post-translational hemoglobin biosynthetic events. In this review, recent experimental results are discussed in light of several current models describing globin subunit folding, heme uptake, assembly, and denaturation during hemoglobin synthesis. Particular attention is devoted to molecular interactions with AHSP that relate to a chain oxidation and the ability of a chains to associate with partner b chains. Antioxid. Redox Signal. 12, 219-232.

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Section: Pathways For Hemoglobin Assembly In Vivo and In Vitromentioning

confidence: 77%

The Role of Alpha-Hemoglobin Stabilizing Protein in Redox Chemistry, Denaturation, and Hemoglobin Assembly

Mollan

Weiss

et al. 2010

Antioxidants & Redox Signaling

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“…(24). Several studies on conformation of nascent proteins on ribosomes and the contribution of ribosome in their folding process point to similar possibilities (17,20,21,23,(25)(26)(27)(28)(29)(30). A number of studies were done in the laboratory of Brimacombe (31), where aminoacylated initiator tRNA and peptidyl tRNA of different lengths obtained by coupled transcription-translation of N-terminal part of different lengths of E. coli ompA protein, bacteriophage T4 gene 60 protein, and tetracycline resistance gene product were photo-cross-linked to the ribosome.…”

Section: Discussionmentioning

confidence: 99%

Complementary Role of Two Fragments of Domain V of 23 S Ribosomal RNA in Protein Folding

Pal¹,

Chandra²,

Chowdhury³

et al. 1999

Journal of Biological Chemistry

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We have shown that the domain V of bacterial 23 S rRNA could fold denatured proteins to their active state. This segment of 23 S rRNA could further be split into two parts. One part containing mainly the central loop of domain V could bind denatured human carbonic anhydrase I stably. This association could be reversed by adding the other part of domain V. The released enzyme was directed in such a way by the central loop of domain V that it could now fold by itself to active form. This agrees with our earlier observation that proteins fold within the cell posttranslationally, a process that is completed after release of the newly synthesized polypeptide from the ribosome (Chattopadhyay, S., Pal, S., Chandra, S., Sarkar, D., and DasGupta, C. (1999) Biochim. Biophys. Acta 1429, 293-298).We have identified the ribosome as a general protein folding modulator on the basis of its ability to successfully fold all the denatured proteins that we have tried so far (e.g. lactate dehydrogenase, glucose-6-phosphate dehydrogenase, horseradish peroxidase, restriction endonucleases, alkaline phosphatase, malate dehydrogenase, ␤-lactamase, carbonic anhydrase, ␤-galactosidase, etc.) (1-6). This in vitro protein folding activity has been found to reside in the domain V of the 23 S rRNA in 50 S particle of the ribosome. This activity of ribosome has also been identified in vivo by showing slow posttranslational activation of the enzyme ␤-galactosidase in Escherichia coli that was synthesized just prior to the addition of the 30 S specific protein synthesis inhibitors kasugamycin and streptomycin. This posttranslational activation, however, was immediately arrested by adding antibiotics that bind to domain V of 23 S rRNA of 50 S ribosomal particle (1). The important question then is whether biological entities like molecular chaperons (7,8) and ribosomes fold proteins to their active states following a pathway basically similar to spontaneous folding or whether there will there be a paradigm shift in our understanding of protein folding in the cell when we know how ribosome (2-6, 9 -11), which synthesizes the polypeptide, also folds it to active form.We identified the protein folding activity in the large loop of domain V of 23 S rRNA of bacterial ribosome (4, 9, 10). We have reported in a number of publications (1-6, 10) that the 70 S bacterial ribosomes, the 80 S wheat germ and rat liver ribosomes, the 50 S bacterial ribosomal subunit, its 23 S rRNA, as well as the 660-nt 1 domain V of 23 S rRNA could all fold denatured proteins, and at the end of the reaction they were found to dissociate completely from the proteins without the assistance of any co-factor. This implied that there were at least two steps in these reactions: (a) interaction with unfolded proteins to fold them and (b) dissociation from the folded proteins. We took the 660-nt-long domain V RNA from Bacillus subtilis and further split it into two smaller pieces that acted in a particular sequence on the unfolded protein to fold it. Here we present the role of these t...

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“…It is important to note, however, that during Hb biosynthesis the monomeric subunits undergo co-translational folding and heme binding [47,48]. Another interesting aspect is the recent discovery of a chaperone in red blood cell precursors.…”

mentioning

confidence: 99%

Folding and assembly of hemoglobin monitored by electrospray mass spectrometry using an on-line dialysis system

Boys

Konermann

2007

J. Am. Soc. Mass Spectrom.

101

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The native structure of hemoglobin (Hb) comprises two ␣-and two ␤-subunits, each of which carries a heme group. There appear to be no previous studies that report the in vitro folding and assembly of Hb from highly unfolded ␣-and ␤-globin in a "one-pot" reaction. One difficulty that has to be overcome for studies of this kind is the tendency of Hb to aggregate during refolding. This work demonstrates that denaturation of Hb in 40% acetonitrile at pH 10.0 is reversible. A dialysis-mediated solvent change to a purely aqueous environment of pH 8.0 results in Hb refolding without any apparent aggregation. Fluorescence, Soret absorption, circular dichroism, and ESI mass spectra of the protein recorded before unfolding and after refolding are almost identical. By employing an externally pressurized dialysis cell that is coupled on-line to an ESI mass spectrometer, changes in heme binding behavior, protein conformation, and quaternary structure can be monitored as a function of time. The process occurs in a stepwise sequential manner, leading from monomeric ␣-and ␤-globin to heterodimeric species, which then assemble into tetramers. Overall, this mechanism is consistent with previous studies employing the mixing of folded ␣-and ␤-globin. However, some unexpected features are observed, e.g., a heme-deficient ␤-globin dimer that represents an off-pathway intermediate. Monomeric ␤-globin is capable of binding heme before forming a complex with an ␣-subunit. This observation suggests that holo-␣-apo-␤ globin does not represent an obligatory intermediate during Hb assembly, as had been proposed previously. The on-line dialysis/ESI-MS approach developed for this work represents a widely applicable tool for studying the folding and self-assembly of noncovalent biological complexes. (J Am Soc Mass Spectrom 2007, 18, 8 -16)

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Cotranslational Folding of Globin

Cited by 142 publications

References 57 publications

The Role of Alpha-Hemoglobin Stabilizing Protein in Redox Chemistry, Denaturation, and Hemoglobin Assembly

The Role of Alpha-Hemoglobin Stabilizing Protein in Redox Chemistry, Denaturation, and Hemoglobin Assembly

Complementary Role of Two Fragments of Domain V of 23 S Ribosomal RNA in Protein Folding

Folding and assembly of hemoglobin monitored by electrospray mass spectrometry using an on-line dialysis system

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