Sandbox Reserved 335: Difference between revisions

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[[Image:heme.gif |frame|left| Figure 2. The tetrapyrrolic heme prosthetic group that can either be covalently attached to or closely associated with various proteins, such as cytochromes and other globin proteins. In ''Rm''cyt''c'', R2 is an ethyl covalently attached to Cys 45, and R3 is a methyl covalently attached to Cys48.]]

The typical monoheme cyt ''c'' fold is formed by helices <scene name='Sandbox_Reserved_335/Helices/2'>A, C, and E</scene>. ''Rm''cyt''c'' contains seven α-helices that are folded around the heme, all connected by random coils.<ref name=main /> The heme group is axially coordinated by <scene name='Sandbox_Reserved_335/Axial/6'>His49 and Met100</scene>, and the disulfide linkages exist at <scene name='Sandbox_Reserved_335/Cys/1'>Cys45 and Cys48</scene>. The heme group in ''Rm''cyt''c'' is almost completely shielded from solvent due to it being in a mostly hydrophobic pocket. This pocket is formed in part by the seven helices surrounding the ring, but also by two structures that are uncommon in cyt ''c''. First, an extension of the N-terminal exists that consists of 21 amino acid residues; this forms an α-helix denoted as A' as well as loop 1, which wraps around the back of the polypeptide.

The typical monoheme cyt ''c'' fold is formed by helices <scene name='Sandbox_Reserved_335/Helices/4'>A, C, and E</scene>. ''Rm''cyt''c'' contains seven α-helices that are folded around the heme, all connected by random coils.<ref name=main /> The heme group is axially coordinated by <scene name='Sandbox_Reserved_335/Axial/6'>His49 and Met100</scene>, and the disulfide linkages exist at <scene name='Sandbox_Reserved_335/Cys/1'>Cys45 and Cys48</scene>. The heme group in ''Rm''cyt''c'' is almost completely shielded from solvent due to it being in a mostly hydrophobic pocket. This pocket is formed in part by the seven helices surrounding the ring, but also by two structures that are uncommon in cyt ''c''. First, an extension of the N-terminal exists that consists of 21 amino acid residues; this forms an α-helix denoted as A' as well as loop 1, which wraps around the back of the polypeptide.

As determined by X-ray crystallography, the ''Rm''cyt''c'' structure was found to also contain a coordinated sulfate ion; this ion has been seen to mediate crystal contact between neighbouring protein molecules. The carboxylate oxygen of Glu122 was also found to be involved in hydrogen bonding with this sulfate ion.<ref name=main />

Sandbox Reserved 335: Difference between revisions

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@@ Line 22: / Line 22: @@
 [[Image:heme.gif |frame|left| Figure 2. The tetrapyrrolic heme prosthetic group that can either be covalently attached to or closely associated with various proteins, such as cytochromes and other globin proteins. In ''Rm''cyt''c'', R2 is an ethyl covalently attached to Cys 45, and R3 is a methyl covalently attached to Cys48.]]
-The typical monoheme cyt ''c'' fold is formed by helices <scene name='Sandbox_Reserved_335/Helices/2'>A, C, and E</scene>. ''Rm''cyt''c'' contains seven α-helices that are folded around the heme, all connected by random coils.<ref name=main /> The heme group is axially coordinated by <scene name='Sandbox_Reserved_335/Axial/6'>His49 and Met100</scene>, and the disulfide linkages exist at <scene name='Sandbox_Reserved_335/Cys/1'>Cys45 and Cys48</scene>. The heme group in ''Rm''cyt''c'' is almost completely shielded from solvent due to it being in a mostly hydrophobic pocket. This pocket is formed in part by the seven helices surrounding the ring, but also by two structures that are uncommon in cyt ''c''. First, an extension of the N-terminal exists that consists of 21 amino acid residues; this forms an α-helix denoted as A' as well as loop 1, which wraps around the back of the polypeptide.
+The typical monoheme cyt ''c'' fold is formed by helices <scene name='Sandbox_Reserved_335/Helices/4'>A, C, and E</scene>. ''Rm''cyt''c'' contains seven α-helices that are folded around the heme, all connected by random coils.<ref name=main /> The heme group is axially coordinated by <scene name='Sandbox_Reserved_335/Axial/6'>His49 and Met100</scene>, and the disulfide linkages exist at <scene name='Sandbox_Reserved_335/Cys/1'>Cys45 and Cys48</scene>. The heme group in ''Rm''cyt''c'' is almost completely shielded from solvent due to it being in a mostly hydrophobic pocket. This pocket is formed in part by the seven helices surrounding the ring, but also by two structures that are uncommon in cyt ''c''. First, an extension of the N-terminal exists that consists of 21 amino acid residues; this forms an α-helix denoted as A' as well as loop 1, which wraps around the back of the polypeptide.
 As determined by X-ray crystallography, the ''Rm''cyt''c'' structure was found to also contain a coordinated sulfate ion; this ion has been seen to mediate crystal contact between neighbouring protein molecules. The carboxylate oxygen of Glu122 was also found to be involved in hydrogen bonding with this sulfate ion.<ref name=main />