User:R. Jeremy Johnson/Folding Synthesis: Difference between revisions
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== '''Introduction''' == | == '''Introduction''' == | ||
Ribonuclease A has been the subject of Nobel Prizes on Protein Folding and Solid Phase Peptide Synthesis.<ref name="Raines"> PMID:11848924</ref> The observation of ribonuclease folding helped Christian Anfinsen win the Nobel Prize in 1972 for his work on protein folding <ref>'Anfinsen Nobel Lecture' [http://nobelprize.org/nobel_prizes/chemistry/laureates/1972/anfinsen-lecture.html]</ref>. The presence of four disulfide bonds and two ''cis'' proline residues in the structure of RNase A greatly | Ribonuclease A has been the subject of Nobel Prizes on Protein Folding and Solid Phase Peptide Synthesis.<ref name="Raines"> PMID:11848924</ref> The observation of ribonuclease folding helped Christian Anfinsen win the Nobel Prize in 1972 for his work on protein folding <ref>'Anfinsen Nobel Lecture' [http://nobelprize.org/nobel_prizes/chemistry/laureates/1972/anfinsen-lecture.html]</ref>. The presence of four disulfide bonds and two ''cis'' proline residues in the structure of RNase A greatly affects the structure and folding kinetics of RNase A <ref>'Anfinsen Nobel Biography' [http://nobelprize.org/nobel_prizes/chemistry/laureates/1972/anfinsen-bio.html]</ref>. When RNase A undergoes reductive denaturation, it spontaneously folds back on itself to form the same structure. The development of solid phase synthesis by Bruce Merrifield was a radical departure from traditional methods of bio-molecular synthesis that greatly increased efficiency. His method made possible the syntheses of much larger and more complex molecules; however, solid phase synthesis was not fully embraced until he demonstrated its full ability with the complete synthesis of Ribonuclease A.[http://nobelprize.org/nobel_prizes/chemistry/laureates/1984/merrifield-lecture.pdf] | ||
== '''Protein Folding''' == | == '''Protein Folding''' == | ||
[[Image:Proteopedia final 2d.png|thumb|280px|left|Residues important to the proper folding of RNase A. Locations of internal residues Pro-114, Pro-117, Cys-58, and Cys-72 are highlighted and labeled.]] | [[Image:Proteopedia final 2d.png|thumb|280px|left|Residues important to the proper folding of RNase A. Locations of internal residues Pro-114, Pro-117, Cys-58, and Cys-72 are highlighted and labeled.]] | ||
Interatomic interactions, delegated by the amino acid sequence, are responsible for formation of a protein's 3D structure [http://en.wikipedia.org/wiki/Protein_folding]. Several of these interactions have been identified by the use of site directed mutagenesis to wildtype RNase A and subsequent comparison of the crystal structure to the wildtype. Although RNase A has 105 possible disulfide bond pairings, only one set of four bonds occurs. This unique observation leads to the "thermodynamic hypothesis", that a protein's native state is determined by the thermodynamic favorability of the whole system; thus the tertiary structure must be predetermined by intramolecular interactions within the amino acid sequence. Since thermodynamic stability of a protein is affected by the environment's temperature, pH, and ionic strength, among other factors, the protein structure can only exist under physiological conditions. Today, the correlation between the amino acid sequence and the tertiary structure of RNase A continues to serve as a model for protein folding. Among the most important attributes of this model are noncovalent interactions, proline conformation, and disulfide bonding <ref name = 'Lehninger'>'Lehninger A., Nelson D.N, & Cox M.M. (2008) Lehninger Principles of Biochemistry. W. H. Freeman, fifth edition.' </ref>. | Interatomic interactions, delegated by the amino acid sequence, are responsible for formation of a protein's 3D structure [http://en.wikipedia.org/wiki/Protein_folding]. Several of these interactions have been identified by the use of site directed mutagenesis to wildtype RNase A and subsequent comparison of the crystal structure to the wildtype. Although RNase A has 105 possible disulfide bond pairings, only one set of four bonds occurs. This unique observation leads to the "thermodynamic hypothesis", that a protein's native state is determined by the thermodynamic favorability of the whole system; thus the tertiary structure must be predetermined by intramolecular interactions within the amino acid sequence.<ref>PMID:132421663</ref> Since thermodynamic stability of a protein is affected by the environment's temperature, pH, and ionic strength, among other factors, the protein structure can only exist under physiological conditions. Today, the correlation between the amino acid sequence and the tertiary structure of RNase A continues to serve as a model for protein folding. Among the most important attributes of this model are noncovalent interactions, proline conformation, and disulfide bonding <ref name = 'Lehninger'>'Lehninger A., Nelson D.N, & Cox M.M. (2008) Lehninger Principles of Biochemistry. W. H. Freeman, fifth edition.' </ref>. | ||
==='''Proline Conformation'''=== | ==='''Proline Conformation'''=== | ||
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=='''References'''== | =='''References'''== | ||
<references /> | <references /> | ||
=='''External Resources'''== | |||
*[http://nobelprize.org/nobel_prizes/chemistry/laureates/1972/anfinsen-lecture.pdf Anfinsen Nobel Prize Lecture] | |||
*[http://nobelprize.org/nobel_prizes/chemistry/laureates/1984/merrifield-lecture.pdf Merrifield Nobel Prize Lecture] | |||
*[http://en.wikipedia.org/wiki/Ribonuclease_A RNase A Wikipedia] | |||
*[http://en.wikipedia.org/wiki/Solid_phase_peptide_synthesis#Solid-phase_synthesis Peptide Synthesis Wikipedia] | |||
*[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2845543/?tool=pmcentrez Chemical Synthesis of Proteins] | |||
*[http://www.ncbi.nlm.nih.gov/pubmed/3680234 Refined Crystal Structure] | |||
=='''Student Contributors'''== | |||
*[http://www.proteopedia.org/wiki/index.php/User:Liz_Ellis Liz Ellis] | |||
*[http://www.proteopedia.org/wiki/index.php/User:Diana_Trautmann Diana Trautmann] | |||
*[http://www.proteopedia.org/wiki/index.php/User:Michael_Slack Lin Liu and Michael Slack] | |||