Saporin: Difference between revisions

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Type 1 RIPS are monomeric, meaning they have one part <ref name="fab">DOI: 10.3390/toxins9100314</ref>. Saporin-S6 at maturity is 256 amino acids long <ref name="ncbi" />. While saporin consists of different residues and molecules, there is only one Chain A in it, and thus is monomeric. Chain A is a polypeptide weighing 30 KDa <ref name="nano">DOI: 10.3390/cancers12020498</ref>. This chain consists of beta-sheets and alpha-helixes. The β-sheets make up the N-terminal domain, while the 𝛼-helix portion is the C-terminal domain <ref name="rcsb" />. In the figure of Chain A, the 𝛼-helices are spiral-shaped strands, while the β-sheets are more of a flat strand.

There is an <scene name='91/910029/Active_site/1'>active site</scene> within this chain that consists of five residues. These residues are <scene name='91/910569/Active_site_tyr/1'>Tyr⁷²</scene>, <scene name='91/910029/Active_site_tyr_120/1'>Tyr¹²⁰</scene>, <scene name='91/910029/Active_site_glu_176/1'>Glu¹⁷⁶</scene>, Arg¹⁷⁹, and Trp²⁰⁸ <ref name="ncbi">DOI: 10.3390/toxins5101698</ref>. Other RIPs also have these same residues in their active sites. The saporin active has Glu¹⁷⁶, Arg¹⁷⁹, and Trp²⁰⁸ in the exact same position as the other ribosome-inactivating proteins. There is a difference in Tyr⁷², which has different side-chain conformations in RIPs and thus is not the same in saporin and other RIPs. This Tyr⁷² is the residue that interacts with the adenine in the cleavage of adenine and the ribosome <ref name="rcsb" />.

There is an <scene name='91/910029/Active_site/1'>active site</scene> within this chain that consists of five residues. These residues are <scene name='91/910569/Active_site_tyr/1'>Tyr⁷²</scene>, <scene name='91/910029/Active_site_tyr_120/1'>Tyr¹²⁰</scene>, <scene name='91/910029/Active_site_glu_176/1'>Glu¹⁷⁶</scene>, <scene name='91/910029/Active_site_arg_179/1'>Arg¹⁷⁹</scene>, and Trp²⁰⁸ <ref name="ncbi">DOI: 10.3390/toxins5101698</ref>. Other RIPs also have these same residues in their active sites. The saporin active has Glu¹⁷⁶, Arg¹⁷⁹, and Trp²⁰⁸ in the exact same position as the other ribosome-inactivating proteins. There is a difference in Tyr⁷², which has different side-chain conformations in RIPs and thus is not the same in saporin and other RIPs. This Tyr⁷² is the residue that interacts with the adenine in the cleavage of adenine and the ribosome <ref name="rcsb" />.

Saporin can also be complexed with other inhibitors. One of these is cyclic tetranucleotide inhibitor in <scene name='91/910569/Complex_of_saporin_with_tetra/1'>complex with saporin-L1</scene>. This can be used because the cyclic tetranucleotide can take the place of the recognition loop for saporin of 28S rRNA <ref name="pnas">DOI: 0.1073/pnas.0911606106</ref>. It is also interesting to note that Ricin can also be complex with other inhibitors like saporin. Saporin is a homologue of Ricin A-Chain which means they are similar in structure <ref name="pnas" />. This ability also allows for saporin-S6 to be conjugated with specific targeting proteins, and thus the saporin-S6 is able to be delivered to the cell. This happens due to the antibodies and is referred to as an immunotoxin <ref name="ncbi" />. The antibodies are recognized by the cell, and the cell binds them. Since the saporin-S6 is in complex with the antibody, it is also taken to the cell. Some other carries can also be used, such as growth factors, antigens, and growth hormones <ref name="ncbi" />.

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@@ Line 8: / Line 8: @@
 Type 1 RIPS are monomeric, meaning they have one part <ref name="fab">DOI: 10.3390/toxins9100314</ref>. Saporin-S6 at maturity is 256 amino acids long <ref name="ncbi" />. While saporin consists of different residues and molecules, there is only one Chain A in it, and thus is monomeric. Chain A is a polypeptide weighing 30 KDa <ref name="nano">DOI: 10.3390/cancers12020498</ref>. This chain consists of beta-sheets and alpha-helixes. The β-sheets make up the N-terminal domain, while the 𝛼-helix portion is the C-terminal domain <ref name="rcsb" />. In the figure of Chain A, the 𝛼-helices are spiral-shaped strands, while the β-sheets are more of a flat strand.
-There is an <scene name='91/910029/Active_site/1'>active site</scene> within this chain that consists of five residues. These residues are <scene name='91/910569/Active_site_tyr/1'>Tyr⁷²</scene>, <scene name='91/910029/Active_site_tyr_120/1'>Tyr¹²⁰</scene>, <scene name='91/910029/Active_site_glu_176/1'>Glu¹⁷⁶</scene>, Arg¹⁷⁹, and Trp²⁰⁸ <ref name="ncbi">DOI: 10.3390/toxins5101698</ref>. Other RIPs also have these same residues in their active sites. The saporin active has Glu¹⁷⁶, Arg¹⁷⁹, and Trp²⁰⁸ in the exact same position as the other ribosome-inactivating proteins. There is a difference in Tyr⁷², which has different side-chain conformations in RIPs and thus is not the same in saporin and other RIPs. This Tyr⁷² is the residue that interacts with the adenine in the cleavage of adenine and the ribosome <ref name="rcsb" />.
+There is an <scene name='91/910029/Active_site/1'>active site</scene> within this chain that consists of five residues. These residues are <scene name='91/910569/Active_site_tyr/1'>Tyr⁷²</scene>, <scene name='91/910029/Active_site_tyr_120/1'>Tyr¹²⁰</scene>, <scene name='91/910029/Active_site_glu_176/1'>Glu¹⁷⁶</scene>, <scene name='91/910029/Active_site_arg_179/1'>Arg¹⁷⁹</scene>, and Trp²⁰⁸ <ref name="ncbi">DOI: 10.3390/toxins5101698</ref>. Other RIPs also have these same residues in their active sites. The saporin active has Glu¹⁷⁶, Arg¹⁷⁹, and Trp²⁰⁸ in the exact same position as the other ribosome-inactivating proteins. There is a difference in Tyr⁷², which has different side-chain conformations in RIPs and thus is not the same in saporin and other RIPs. This Tyr⁷² is the residue that interacts with the adenine in the cleavage of adenine and the ribosome <ref name="rcsb" />.
 Saporin can also be complexed with other inhibitors. One of these is cyclic tetranucleotide inhibitor in <scene name='91/910569/Complex_of_saporin_with_tetra/1'>complex with saporin-L1</scene>. This can be used because the cyclic tetranucleotide can take the place of the recognition loop for saporin of 28S rRNA <ref name="pnas">DOI: 0.1073/pnas.0911606106</ref>. It is also interesting to note that Ricin can also be complex with other inhibitors like saporin. Saporin is a homologue of Ricin A-Chain which means they are similar in structure <ref name="pnas" />. This ability also allows for saporin-S6 to be conjugated with specific targeting proteins, and thus the saporin-S6 is able to be delivered to the cell. This happens due to the antibodies and is referred to as an immunotoxin <ref name="ncbi" />. The antibodies are recognized by the cell, and the cell binds them. Since the saporin-S6 is in complex with the antibody, it is also taken to the cell. Some other carries can also be used, such as growth factors, antigens, and growth hormones <ref name="ncbi" />.