Molten globules

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In biochemistry , molten globule (in English 'melted spherical shape') describes a protein structure in some proteins that is between the native form and the denatured form and can be distinguished from these forms.

properties

The molten globule was first described in 1983 for cytochrome c by M. Ohgushi and A. Wada. At high concentrations of salts or low pH (pH 2), cytochrome c takes a form with a less densely packed center than the native form. This allows small molecules to diffuse inside these proteins. The molten globule shape can partly also be achieved by mild denaturation. The transition of the forms into each other runs in these proteins from native ↔ molten globule ↔ denatured, whereby a cooperativity of the forms was assumed during the conversion. During the transition from the native to the molten globule form, changes primarily occur in the tertiary structure of the proteins. This is why the molten globule shape was also referred to as the third phase of some proteins.

When protein design is trying to make a molten globule - to avoid or a denatured form of the protein.

Examples of proteins with molten globule form are cytochrome c, apomyoglobin , flavodoxin -like proteins, α-lactalbumin , the P2 protein from Plasmodium falciparum and CylR2 . Some intrinsically unstructured proteins have a molten globule shape.

Individual evidence

  1. ↑ M. Ohgushi, A. Wada: 'Molten globule state': a compact form of globular proteins with mobile side-chains. In: FEBS letters. Volume 164, Number 1, November 1983, pp. 21-24, PMID 6317443 .
  2. ^ RL Baldwin, GD Rose: Molten globules, entropy-driven conformational change and protein folding. In: Current opinion in structural biology. Volume 23, number 1, February 2013, pp. 4–10, doi : 10.1016 / j.sbi.2012.11.004 , PMID 23237704 .
  3. ↑ Y. Kuroda, S. Kidokoro, A. Wada: Thermodynamic characterization of cytochrome c at low pH. Observation of the molten globule state and of the cold denaturation process. In: Journal of molecular biology. Volume 223, Number 4, February 1992, pp. 1139-1153, PMID 1311387 .
  4. ↑ VS Pande, DS Rokhsar: Is the molten globule a third phase of proteins? In: Proceedings of the National Academy of Sciences . Volume 95, Number 4, February 1998, pp. 1490-1494, PMID 9465042 , PMC 19058 (free full text).
  5. ↑ MK Khan, H. Rahaman, F. Ahmad: Conformation and thermodynamic stability of pre-molten and molten globule states of mammalian cytochromes-c. In: Metallomics: integrated biometal science. Volume 3, Number 4, April 2011, pp. 327-338, doi : 10.1039 / c0mt00078g , PMID 21431228 .
  6. ↑ PJ Elms, JD Chodera, C. Bustamante, S. Marqusee: The molten globule state is unusually deformable under mechanical force. In: Proceedings of the National Academy of Sciences . Volume 109, number 10, March 2012, pp. 3796-3801, doi : 10.1073 / pnas.1115519109 , PMID 22355138 , PMC 3309780 (free full text).
  7. ↑ YES Houwman, CP van Mierlo: Folding of proteins with a flavodoxin-like architecture. In: The FEBS journal. Volume 284, Number 19, October 2017, pp. 3145-3167, doi : 10.1111 / febs.14077 , PMID 28380286 .
  8. ↑ EA Permyakov, SE Permyakov, L. Breydo, EM Redwan, HA Almehdar, VN Uversky: Disorder in Milk Proteins: α-lactalbumin. Part A. Structural Properties and Conformational Behavior. In: Current protein & peptide science. Volume 17, Number 4, 2016, pp. 352-367, PMID 26956441 .
  9. ↑ P. Mishra, S. Choudhary, S. Mukherjee, D. Sengupta, S. Sharma, RV Hosur: Molten globule nature of P2 homo-tetramer. In: Biochemistry and biophysics reports. Volume 1, May 2015, pp. 97-107, doi : 10.1016 / j.bbrep.2015.03.010 , PMID 29124138 , PMC 5668626 (free full text).
  10. ↑ M. Jaremko, Ł. Jaremko, HY Kim, MK Cho, CD Schwieters, K. Giller, S. Becker, M. Zweckste: Cold denaturation of a protein dimer monitored at atomic resolution. In: Nature chemical biology. Volume 9, number 4, April 2013, pp. 264-270, doi : 10.1038 / nchembio.1181 , PMID 23396077 , PMC 5521822 (free full text).
  11. ↑ UN Uversky: Biophysical Methods to Investigate Intrinsically Disordered Proteins: Avoiding an "Elephant and Blind Men" situation. In: Advances in Experimental Medicine and Biology . Volume 870, 2015, pp. 215-260, doi : 10.1007 / 978-3-319-20164-1_7 , PMID 26387104 .