Limits...
Independent of their localization in protein the hydrophobic amino acid residues have no effect on the molten globule state of apomyoglobin and the disulfide bond on the surface of apomyoglobin stabilizes this intermediate state.

Melnik TN, Majorina MA, Larina DS, Kashparov IA, Samatova EN, Glukhov AS, Melnik BS - PLoS ONE (2014)

Bottom Line: In this study, we have investigated the effect of substitutions of hydrophobic amino acid residues in the hydrophobic core of protein and on its surface on a molten globule type intermediate state of apomyoglobin.It has been found that independent of their localization in protein, substitutions of hydrophobic amino acid residues do not affect the stability of the molten globule state of apomyoglobin.The result obtained allows us not only to conclude which mutations can have an effect on the intermediate state of the molten globule type, but also explains why the introduction of a disulfide bond (which seems to "strengthen" the protein) can result in destabilization of the protein native state of apomyoglobin.

View Article: PubMed Central - PubMed

Affiliation: Institute of Protein Research, RAS, Pushchino, Moscow Region, Russia.

ABSTRACT
At present it is unclear which interactions in proteins reveal the presence of intermediate states, their stability and formation rate. In this study, we have investigated the effect of substitutions of hydrophobic amino acid residues in the hydrophobic core of protein and on its surface on a molten globule type intermediate state of apomyoglobin. It has been found that independent of their localization in protein, substitutions of hydrophobic amino acid residues do not affect the stability of the molten globule state of apomyoglobin. It has been shown also that introduction of a disulfide bond on the protein surface can stabilize the molten globule state. However in the case of apomyoglobin, stabilization of the intermediate state leads to relative destabilization of the native state of apomyoglobin. The result obtained allows us not only to conclude which mutations can have an effect on the intermediate state of the molten globule type, but also explains why the introduction of a disulfide bond (which seems to "strengthen" the protein) can result in destabilization of the protein native state of apomyoglobin.

Show MeSH
Energy schemes for proteins with different types of intermediate state and schematic representation of different states of such proteins.A, Scheme for a protein in which native and intermediate states differ in their properties. In this case it is possible to choose the mutation that will act selectively on one of the protein states, for example, on the intermediate state (shown in red color). B, Scheme for a protein in which the intermediate state is a partially “destroyed” native state. In this case states I and N are stabilized by similar interactions and the mutation affecting state I will also affect state N. This effect (decreasing free energy for I and N) is shown in red. N. I and U are native, intermediate and unfolded states of the protein, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4043776&req=5

pone-0098645-g008: Energy schemes for proteins with different types of intermediate state and schematic representation of different states of such proteins.A, Scheme for a protein in which native and intermediate states differ in their properties. In this case it is possible to choose the mutation that will act selectively on one of the protein states, for example, on the intermediate state (shown in red color). B, Scheme for a protein in which the intermediate state is a partially “destroyed” native state. In this case states I and N are stabilized by similar interactions and the mutation affecting state I will also affect state N. This effect (decreasing free energy for I and N) is shown in red. N. I and U are native, intermediate and unfolded states of the protein, respectively.

Mentions: At first sight, this conclusion may seem trivial. Indeed, if the free energy of the intermediate state in the energy scheme of any three-state protein (for example, see the scheme in Fig. 8A) is decreased by introduction of the mutation, the transition between the native N and intermediate states I would be destabilized while the transition between the intermediate I and unfolded states U would be stabilized. But such behavior of energy levels in a definite protein means that the native state N and the intermediate states I are stabilized by different interactions independent of each other.


Independent of their localization in protein the hydrophobic amino acid residues have no effect on the molten globule state of apomyoglobin and the disulfide bond on the surface of apomyoglobin stabilizes this intermediate state.

Melnik TN, Majorina MA, Larina DS, Kashparov IA, Samatova EN, Glukhov AS, Melnik BS - PLoS ONE (2014)

Energy schemes for proteins with different types of intermediate state and schematic representation of different states of such proteins.A, Scheme for a protein in which native and intermediate states differ in their properties. In this case it is possible to choose the mutation that will act selectively on one of the protein states, for example, on the intermediate state (shown in red color). B, Scheme for a protein in which the intermediate state is a partially “destroyed” native state. In this case states I and N are stabilized by similar interactions and the mutation affecting state I will also affect state N. This effect (decreasing free energy for I and N) is shown in red. N. I and U are native, intermediate and unfolded states of the protein, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4043776&req=5

pone-0098645-g008: Energy schemes for proteins with different types of intermediate state and schematic representation of different states of such proteins.A, Scheme for a protein in which native and intermediate states differ in their properties. In this case it is possible to choose the mutation that will act selectively on one of the protein states, for example, on the intermediate state (shown in red color). B, Scheme for a protein in which the intermediate state is a partially “destroyed” native state. In this case states I and N are stabilized by similar interactions and the mutation affecting state I will also affect state N. This effect (decreasing free energy for I and N) is shown in red. N. I and U are native, intermediate and unfolded states of the protein, respectively.
Mentions: At first sight, this conclusion may seem trivial. Indeed, if the free energy of the intermediate state in the energy scheme of any three-state protein (for example, see the scheme in Fig. 8A) is decreased by introduction of the mutation, the transition between the native N and intermediate states I would be destabilized while the transition between the intermediate I and unfolded states U would be stabilized. But such behavior of energy levels in a definite protein means that the native state N and the intermediate states I are stabilized by different interactions independent of each other.

Bottom Line: In this study, we have investigated the effect of substitutions of hydrophobic amino acid residues in the hydrophobic core of protein and on its surface on a molten globule type intermediate state of apomyoglobin.It has been found that independent of their localization in protein, substitutions of hydrophobic amino acid residues do not affect the stability of the molten globule state of apomyoglobin.The result obtained allows us not only to conclude which mutations can have an effect on the intermediate state of the molten globule type, but also explains why the introduction of a disulfide bond (which seems to "strengthen" the protein) can result in destabilization of the protein native state of apomyoglobin.

View Article: PubMed Central - PubMed

Affiliation: Institute of Protein Research, RAS, Pushchino, Moscow Region, Russia.

ABSTRACT
At present it is unclear which interactions in proteins reveal the presence of intermediate states, their stability and formation rate. In this study, we have investigated the effect of substitutions of hydrophobic amino acid residues in the hydrophobic core of protein and on its surface on a molten globule type intermediate state of apomyoglobin. It has been found that independent of their localization in protein, substitutions of hydrophobic amino acid residues do not affect the stability of the molten globule state of apomyoglobin. It has been shown also that introduction of a disulfide bond on the protein surface can stabilize the molten globule state. However in the case of apomyoglobin, stabilization of the intermediate state leads to relative destabilization of the native state of apomyoglobin. The result obtained allows us not only to conclude which mutations can have an effect on the intermediate state of the molten globule type, but also explains why the introduction of a disulfide bond (which seems to "strengthen" the protein) can result in destabilization of the protein native state of apomyoglobin.

Show MeSH