proteins amino acids - 2 Flashcards
(23 cards)
where are the hydrogen bonds in a beta sheet ?
between the peptide bonds
whats stronger arrangement , parallel or antiparallel ?
antiparallel as bonds are better aligned and stronger.
whats the arrangment of the side chains in a beta sheet ?
they stick out the front and face behind
what determined if an amino acid reside becomes a helix , sheet or turn conformation ?
the side chains
whats the role of PRO and GLY
PRO causes a turn in chain while GLY tucks in
what is the tertiary structure ?
the final 3D shape of a protein
what occurs during the packing together of the sections in a protein ?
it excludes solvent molecules from the interior
in helix to helix packing what is mainly involved ?
the side chains that stick out from the helix surface
in helix to sheet packing what is the tendency of the axes ?
tend to be nearly parallel
in sheet to sheet packing what are the 2 main possibilities ?
aligned or orthogonal
explain aligned
face to face packing of 2 sheets
explain orthogonal ?
this is when one sheet folds back on itself
what two bonds help to stabalise the tertiary structure ?
disulfide bridges between adjacent strands and hydrogen bonds between peptide bonds and side chains
what are the domains like in large proteins ?
these are compact local folded regions of the polypeptide that have functions specific to each domains
what is a quaternary structure ?
contains 2 or more subunits that are folded to give a complex , sub units are held together by h bonds and disulphide bridges
are the subunits identical?
can be but also be different
whats the 2 groups of proteins ?
fibrous and globular
whats the role of fiborous proteins ?
they are long proteins that are mainly have a structural role in cell i.e keratin and collagen
what is a globular protein ?
this is when theres a mixture of short helices and sheets , mainly water soluble
features of collagen ?
it is rigid , fibrous composed of 3 helixes
the collagen fibres pack together to form what and how is it stabilised ?
a collagen fibril is stabilised by hydrogen bonds
what structure are prosthetic groups found in ?
tertiary
what is tropocollagen ?
this is a glycoprotein , that has sugars glucose and galactose linked to its chains
