Fibroins: Difference between revisions
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Fibroins are proteins that constitute silk fibers. Fibroins are large complex proteins and the specific structural details of those making up different types of silk are different, but all fibroins have some common characteristics. Interesting general information on spider silk and a model of one type of a spider silk molecule is at<ref>[http://en.wikipedia.org/wiki/Spider_silk Wikipedia]</ref>. This model of spider silk shows two repeating domains that all fibroins contain. One domain is characterized as being amorphous, also called flexible, disordered segments, and the other one, symbolized by the boxes, has a highly ordered, repetitive, crystal-like structure. The objective of this exercise is to explicate this <b>ordered</b> domain of | <StructureSection load='3ua0' size='350' side='right' caption='Silkworm fibroin N-terminal (PDB entry [[3ua0]])' scene=''> | ||
'''Fibroins''' are proteins that constitute silk fibers<ref>PMID:15132657</ref>. Fibroins are large complex proteins and the specific structural details of those making up different types of silk are different, but all fibroins have some common characteristics. See also [[Fibrous Proteins]]. Interesting general information on spider silk and a model of one type of a spider silk molecule is at<ref>[http://en.wikipedia.org/wiki/Spider_silk Wikipedia]</ref>. This model of spider silk shows two repeating domains that all fibroins contain. One domain is characterized as being amorphous, also called flexible, disordered segments, and the other one, symbolized by the boxes, has a highly ordered, repetitive, crystal-like structure. The objective of this exercise is to explicate this <b>ordered</b> domain of <scene name='Fibroins/Chain_a/1'>fibroins</scene>. | |||
===Repetitive peptide segment & β-sheet=== | ===Repetitive peptide segment & β-sheet=== | ||
Displayed here is a peptide segment that is present in many fibroin proteins that are found in silk fibers. | Displayed here is a peptide segment that is present in many fibroin proteins that are found in silk fibers. It is repeated many times to make up the ordered, repetitive structure of the crystalline domain of the fibroin. | ||
<Br> | <Br> | ||
Determine the sequence of the segment by hovering over the residues taking time to consider the nature of their side chains and from which direction their side chains project from the backbone. All the Gly need to be on the same side of the peptide in order to construct the silk fiber. Labels describe how | Determine the sequence of the segment by hovering over the residues taking time to consider the nature of their side chains and from which direction their side chains project from the backbone. All the Gly need to be on the same side of the peptide in order to construct the silk fiber. Labels describe how <scene name='Fibroins/Chain_a_2/1'>hexapeptides are connected</scene> together to produce a longer polypeptide. | ||
A two strand β-sheet is formed by <scene name='Fibroins/Chains_ab/2'>two hexapeptides</scene> positioned antiparallel with respect to each other. Show <scene name='Fibroins/Chains_ab_3/2'>hbonds</scene> which hold | A two strand β-sheet is formed by <scene name='Fibroins/Chains_ab/2'>two hexapeptides</scene> positioned antiparallel with respect to each other. Show interchain <scene name='Fibroins/Chains_ab_3/2'>hbonds</scene> which hold chains together. Show <scene name='Fibroins/Chains_ab_3/1'>spacefill</scene> display. | ||
Adding two more chains to form a <scene name='Fibroins/Four_strands/2'>four stranded beta-sheet</scene>. Show <scene name='Fibroins/Four_strands_2/1'>spacefill</scene> rendition. | |||
Two <scene name='Fibroins/Two_sheets/1'>stacked sheets</scene>. Show <scene name='Fibroins/Two_sheets_2/1'>hbonds</scene>. | Two <scene name='Fibroins/Two_sheets/1'>stacked sheets</scene>. The two sheets come together so that the 'Ala side chains' face each other with the methyl and hydroxymethyl groups intercalated. These sheets are attracted to each other and held in place by the hydrophobic forces generated between these side chains. Show interchain <scene name='Fibroins/Two_sheets_2/1'>hbonds</scene> within each sheet. <scene name='Fibroins/Two_sheets_3/1'>Spacefill display</scene> shows that the methyl side chains of the two sheets are close enough to produce hydrophobic forces and that the backbone atoms are close enough to form hbonds. | ||
A <scene name='Fibroins/Three_sheets/1'>third sheet</scene> is stacked with the other two so that the Gly side chains (hydrogen atoms) intercalate. Show <scene name='Fibroins/Three_sheets_2/1'>interchain hbonds</scene> of all three sheets. <scene name='Fibroins/Three_sheets_3/1'>Spacefill rendition</scene> shows that where the Gly side chains come together the backbonds of the sheets are much closer to each other. | |||
<scene name=' | Each wireframe chain <scene name='Fibroins/Multicolored/2'>colored differently</scene>. Show <scene name='Fibroins/Multicolored_2/2'>spacefill rendition</scene>. | ||
</StructureSection> | </StructureSection> | ||
== 3D Structures of fibroin == | |||
Updated on {{REVISIONDAY2}}-{{MONTHNAME|{{REVISIONMONTH}}}}-{{REVISIONYEAR}} | |||
[[3ua0]] – Fib heavy chain – silkworm<br /> | |||
[[2khm]] – Fib-3 C-terminal – spider - NMR<br /> | |||
[[2m0m]] – NaFib-1 residues 250-356 – Nephila antipodiana - NMR<br /> | |||
[[2mqa]] – NaFib-1 RP domain residues 32-163 - NMR<br /> | |||
== References == | |||
<references /> | <references /> | ||
[[Category:Topic Page]] | |||
Latest revision as of 13:11, 24 May 2018
Fibroins are proteins that constitute silk fibers[1]. Fibroins are large complex proteins and the specific structural details of those making up different types of silk are different, but all fibroins have some common characteristics. See also Fibrous Proteins. Interesting general information on spider silk and a model of one type of a spider silk molecule is at[2]. This model of spider silk shows two repeating domains that all fibroins contain. One domain is characterized as being amorphous, also called flexible, disordered segments, and the other one, symbolized by the boxes, has a highly ordered, repetitive, crystal-like structure. The objective of this exercise is to explicate this ordered domain of . Repetitive peptide segment & β-sheetDisplayed here is a peptide segment that is present in many fibroin proteins that are found in silk fibers. It is repeated many times to make up the ordered, repetitive structure of the crystalline domain of the fibroin.
A two strand β-sheet is formed by positioned antiparallel with respect to each other. Show interchain which hold chains together. Show display. Adding two more chains to form a . Show rendition. Two . The two sheets come together so that the 'Ala side chains' face each other with the methyl and hydroxymethyl groups intercalated. These sheets are attracted to each other and held in place by the hydrophobic forces generated between these side chains. Show interchain within each sheet. shows that the methyl side chains of the two sheets are close enough to produce hydrophobic forces and that the backbone atoms are close enough to form hbonds. A is stacked with the other two so that the Gly side chains (hydrogen atoms) intercalate. Show of all three sheets. shows that where the Gly side chains come together the backbonds of the sheets are much closer to each other. Each wireframe chain . Show . |
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3D Structures of fibroin3D Structures of fibroin
Updated on 24-May-2018
3ua0 – Fib heavy chain – silkworm
2khm – Fib-3 C-terminal – spider - NMR
2m0m – NaFib-1 residues 250-356 – Nephila antipodiana - NMR
2mqa – NaFib-1 RP domain residues 32-163 - NMR
ReferencesReferences
- ↑ Sohn S, Strey HH, Gido SP. Phase behavior and hydration of silk fibroin. Biomacromolecules. 2004 May-Jun;5(3):751-7. PMID:15132657 doi:http://dx.doi.org/10.1021/bm0343693
- ↑ Wikipedia