Pseudoeurotium indicum (Chattopadhyay &amp; Das Gupta) comb.nov.

Chattopadhyay, Sailesh

doi:10.1016/s0007-1536(57)80049-7

Cited by 5 publications

(1 citation statement)

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“…Since the ribosomes from all sources possess the PTC, having remarkably similar secondary structures, it is not surprising to find that all the PTCs from different sources have protein synthesizing and folding properties which we and others have observed. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] At this point, it should be possible to take the PTC out of the large subunit context and check whether it can fold proteins in vitro. That would make it possible to work out the physico-chemical mechanism of this process.…”

Section: Protein Folding: In Vivo To In Vitromentioning

confidence: 99%

Ribosome: The Structure–Function Relation and a New Paradigm to the Protein Folding Problem

Das

Samanta

Das

et al. 2010

Israel Journal of Chemistry

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The rate of protein synthesis is about seven and fifteen amino acids per second, in the eukaryotic and the bacterial ribosome, respectively. Hence, a few minutes is required to synthesize a polypeptide of an average length. This is much longer than the time needed for the hydrophobic collapse (folding) to take place. So a polypeptide gets enough time to form its local secondary to tertiary structures cotranslationally and put such segments in proper order while in association with the ribosome, unless something prevents its entire length from folding. As reported earlier, ribosomes from prokaryotes, eukaryotes, and mitochondria act as molds for protein folding, and each mold has a set of recognition sites for all proteins. More specifically, the mold is the peptidyl transferase center (PTC), a part of the large RNA of the large ribosomal subunit. Specific amino acids from different random coil regions in a protein interact with specific nucleotides in the PTC, which brings the entire length of the protein into the small space of the PTC mold. The mold thus helps to stabilize the entropy‐driven collapsed state of the polypeptide. The process also divides the protein into small segments; each segment is connected at two ends with two nucleotides and can fold in the ribosomal environment. The segments dissociate in such a sequence that the organization proceeds hierarchically from the core of the globular protein radially towards the outer surface. Then the protein dissociates from the ribosome in a “folding competent state” which does the final fine tuning in folding outside the ribosome. While the ribosomal contact and release are over in 1–2 minutes in vitro, the fine tuning takes about 5–10 minutes. Release from the ribosome needs no added energy factor from outside, like ATP.

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