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- rod like
- CO & NH of the mainchain are hydrogen bonded together, allowing the mainchain to be buried
- n+4 H bonding scheme
- all alpha carbons are H bonded and in line with each other
- R groups are on the outside & backbone on the inside
- always right handed (clockwise)
- can be a single chain (usually less than 45 Angstroms)
- Residues that are 1 & 2 residues apart are on opposite sides, while residues that are 3 & 4 residues apart are on the same side; this allows small steric hindrance
- 1.5 Angstroms rise (from one alpha carbon to the second)
- 100 degree rotation
- 3.6 residues per turn
- Ramachandran diagrams (1) Right handed: can only occur between -60, -60; little hindrance (2) Left handed: +60, +60; large hindrance
- sheet like
- Beta sheets are formed by linking 2 or more Beta strands by H bonds
- side chain of adjacent residues point in opposite directions
- only trans peptide bonds give R groups on opposite sides
- cannot exist as a single Beta strand; must be 2 or more
- in proteins, 4-5 strands make up a beta sheet; it is possible to be made of more than 10
- 3.5 Angstroms rise between residues
- 7 Angstroms between R groups
- Arrow in pictures always points to the CO group
- can be antiparallel, parallel, or mixed
- anti: 1:1; alpha carbons are completely lined up across from each other; CO & NH of adjacent strands are H bonded together; chains are in opposite directions
- parallel: strands are in the same direction; NH group of the first chain is bonded to the CO of the 2nd chain through H bond, then move two residues to the right and the CO of the first chain is H bonded to the NH of the 2nd chain.
- Ramachandran diagrams: exists between -60 to -120, 100-190
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SteveA beta strand is a single chain of amino acids with a specific conformation, while a beta sheet is formed when two or more beta strands align and hydrogen bond with each other. Beta strands are the building blocks of beta sheets, which are a common secondary structure in proteins.
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What is a beta pleated sheet in DNA?
A regular element of secondary structure in proteins, in which two or more extended strands of the polypeptide chain lie side by side (running either parallel or antiparallel), held together by a regular array of hydrogen bonds between backbone NH and C=O groups, to form a ridged planar surface. The amino-acid side chains alternately face to opposite sides of the sheet.
What level of molecular organization is a beta-folded sheet?
A beta-folded sheet is a secondary structure of a protein, which is the next level of molecular organization above the primary structure. It is formed by hydrogen bonding between adjacent segments of a polypeptide chain, creating a flat and elongated sheet-like structure.
What is the difference between a beta plus particle and a beta minus particle?
The difference between a beta plus and beta minus particle is the electrical charge. The charges are equal, but opposite. The beta minus particle is an electron with a negative charge, while the beta plus particle is an anti-electron or positron with a positive charge.
What do you call the 2 types of secondary protein structure which are evident in a polypeptide cha in?
The two types of secondary protein structure are alpha helix and beta sheet. In an alpha helix, the polypeptide chain is tightly coiled in a helical shape, while in a beta sheet, the polypeptide chain is folded into a sheet-like structure with hydrogen bonds between neighboring strands.
How many beta sheet hemoglobin have?
Hemoglobin does not contain beta sheets. It is a globular protein composed of four subunits - two alpha and two beta subunits in adults (hemoglobin A). Each subunit consists of alpha-helices, not beta sheets.
