MHC Class I and Class II Structure, Function and Difference (Major Histocompatibility Complex)

MHC- Tightly linked complex of genes encoding for cell surface molecules that are required for antigen presentation and rapid graft rejection.General organization and inheritance of MHCHistocompatibility antigens- Rejection of foreign tissues is a result of an immune response to cell surface molecules. This concept is known as histocompatibility antigens.MHC ENCODES THREE MAJOR CLASSES OF MOLECULESThe MHC complex is a tight collection of genes.The MHC is referred to as the HLA complex (located on chromosome 6) in humans and H2 complex (chromosome 17 ) in miceSTRUCTURE OF MHC CLASS I• Class I MHC molecules contain a 45kDa α chain (transmembrane glycoprotein encoded by ABC region of HLA complex) and a 12kDa β2 microglobulin molecule.• α chain contains 3 external domains (α1, α2 and α3), each contain approx. 90 amino acids• α chain contains a transmemebrane domain of approx. 25 hydrophobic amino acids followed by a small stretch of charged (hydrophilic) amino acids.• It also contains a cytoplasmic anchor segment of 30 amino acids• α1 and α2 interact to form 8 antiparallel β strands spanned by 2 α helices. This forms a deep groove or cleft of approx. 25Å X 10 Å X 11 Å with α helices as sides and β strands as the bottom. This peptide binding cleft is located on the top surface of the MHC molecule.• It can bind a peptide of 8-10 amino acids• α 3 and β2 are organized into 2β pleated sheets formed by antiparallel β strands.• α 3 is highly conserved and contains a sequence that interacts with CD8 molecules of Tc cells• β2 interacts with α 3 and also with α1 and α2. Interaction of β2 is important for a fully folded conformation.Assembly of Class I molecules• β2 microglobulin interact with α3 chain and helps the folding of α chain.• This structure is stabilized by binding of appropriate peptide to form naïve Class I structure. • This assembly is transported to the cell surface.• α 3 and β2 association is important for expression of Class I molecules on cell surface. If no interaction between them,then no active MHC.STRUCTURE OF MHC CLASS II• Class II molecules contain a 33kDa αchain (90 amino acids) and a 28kDa βchain (25 amino acids) which are associated by non covalent interactions.• They are membrane bound glycoproteins with external domain, transmemebrane domain and a cytoplasmic anchor segment.• There are two external domains: α1 and α2 domain, β1 and β2 domain.• Peptide binding cleft structure is similar to that in Class I MHC molecules, however class II molecules forms an open pocket instead of a closed pocket (due to lack of conserved residues that bond the terminal residues of short peptides).

John Thien

My favorite is the 60 yard shot

Edvanolm M

Rip big black

Nolo Aldaeri

Did I only find that "pretty, if a little thin" is YTTƎЯꟼ offense?

Kyle McCarthy

Cody is fish licker

Guy Dahan

I bet there is

Chillz_Musicz

1:12

cindy esposito

its for my son.

Paradox Brother

I remember there was mention of a Hybridpanda Easter egg (I believe he was one of the beta testers, and he does a play through of the game on his channel), but I can't confirm nor deny this. He made mention of it, but I can't remember if he's found it or not.

Kevin Herbst

why is it that whenever something cool happens on the internet ppl call it fake

Alisha Nasir

That instructor is stupid doesn't he know that you take off that first parachute then open the emergency parachute like dude that's your job

ameera abualsamh

Love the whistle. Every ref should use it , very smart Cody . Oh and thanks for telling that man to put on shorts. Lol

Naomi Aaronson

Did anyone else think it said ass burger syndrome at first?😂 but I totally respect people that have this so no hate that’s just what I heard ok?😁

Mustafa MfM

I need the music plz 7:05

Refract ミラー 404

Keanu is the cherry on top to this already awesome game!

Danny Britton

Ty try 100 yards

Renus

i wonder how many basketball they used

LegoStopMotions99

no skyrim was made in 2012

1K subs with no videos challenge

I felt bad for the doggie 😭😭

Woosh/ 1

They should have put the “ball don’t lie guy”

Jordan Johnson

who else thought she meant that her family ate junk food when you clicked? 😆

phi0816

Should be a quarterback for the MN vikings :D

Sanjay Verma

We want pool trick shots battle 3

Kirito

SOORRRAAAAA

Sow Kis

This is so sweet