bchm lecture 9 (protein motifs and domain`s)

what is a motif

a specific amino acid structure that will give you a specific fold

what is a domain

multiple folds coming together

does a domain self fold?

yes

in terms of domains, tertiary structure can have multiple of them

true

what happens if folds dont stay folded?

they dont have function

what is the most prevelant motif

beta-alpha-beta fold

what can proteins have multiple of

domains

what does a quaternary structure depend on

the same/different type of protein and the number of proteins

what are proteins classes based on

structure and solubility

describe fibrous proteins

they look insoluble, collagen like

describe globular proteins

free floating, come off the ribosome

what are some highly talked about globular proteins

myoglobin, ezymes, etc

where are we later going to talk about membrane proteins

the etc

what is true about proteins and their folds

they can have different folds with the same function, but they can also have different functions with the same fold

what is the most common protein fold in all proteins

ab- barrel

what is the full name of the alpha beta barrel

triosephosphateisomerase

whats special about the ab-barrel

its a very similar fold to a lot of different proteins, but there are many different functions

what are the two things that can denature proteins

heat and chemicals

what is a good reducing agent for proteins

beta mercaptoethanol

what interrupts hydrogen bonding in proteins

urea

what is a common structure in fibrous proteins

coiled coil motifs

what is a coiled coil motif

a bundle of alpha helices that are wound into a superhelix

how many segments can be found in a coiled coil bundle

2,3 or 4

how are coiled coils characterized

by a distinctive and regular packing of side chains in the core of the bundle

for fibrous proteins, what are the three main fibrous proteins

microfilaments, microtubules, and intermediate fillaments

what are microfillaments made of

actin

what are the three proteins that make up intermediate filaments

vimentin, nestin, and keratin

what makes up microtubules

tubulin

what filaments are ropelike to help stabilize a cells shape and structure

intermediate

what protein is made of hollow cylinders (that are also made of an alpha and beta subunti)

microtubules, tubulins have the two subunits

what is an important protein in cancer cells

actin

what protein makes up hair, nails, and epidermis?

alpha keratin