6GB5

H2-Db binding "FAPGNYP" at 2.30Å resolution

Data provenance

Structure downloaded from PDB Europe using the Coordinate Server. Aligned to residues 1-180 of 1HHK2 using the CEALIGN3 function of PyMol4. Chain assigment using a Levenshtein distance5 method using data from the PDBe REST API6. Organism data from PDBe REST API. Data for both of these operations from the Molecules endpoint. Structure visualised with 3DMol7.

Complex type

Class i with peptide

1. Beta 2 microglobulin

['B', 'D']

2. Class I alpha
H2-Db

['A', 'C']

3. Peptide
FAPGNYP

['G', 'H']

Species

Mus musculus (Mouse)

Locus / Allele group

H2-D / H2-Db

Publication

Successive crystal structure snapshots suggest the basis for MHC class I peptide loading and editing by tapasin.

Hafstrand I, Sayitoglu EC, Apavaloaei A, Josey BJ, Sun R, Han X, Pellegrino S, Ozkazanc D, Potens R, Janssen L, Nilvebrant J, Nygren PÅ, Sandalova T, Springer S, Georgoudaki AM, Duru AD, Achour A

Proc. Natl. Acad. Sci. U.S.A. (2019) [doi:10.1073/pnas.1807656116] [pubmed:30808808]

MHC-I epitope presentation to CD8⁺ T cells is directly dependent on peptide loading and selection during antigen processing. However, the exact molecular bases underlying peptide selection and binding by MHC-I remain largely unknown. Within the peptide-loading complex, the peptide editor tapasin is key to the selection of MHC-I-bound peptides. Here, we have determined an ensemble of crystal structures of MHC-I in complex with the peptide exchange-associated dipeptide GL, as well as the tapasin-associated scoop loop, alone or in combination with candidate epitopes. These results combined with mutation analyses allow us to propose a molecular model underlying MHC-I peptide selection by tapasin. The N termini of bound peptides most probably bind first in the N-terminal and middle region of the MHC-I peptide binding cleft, upon which the peptide C termini are tested for their capacity to dislodge the tapasin scoop loop from the F pocket of the MHC-I cleft. Our results also indicate important differences in peptide selection between different MHC-I alleles.

Structure deposition and release

Deposited: 2018-04-13

Released: 2019-03-06

Revised: 2019-03-20

Data provenance

Publication data retrieved from PDBe REST API8 and PMCe REST API9

Other structures from this publication

Peptide details

Length: Heptamer (7 amino acids)

Sequence: FAPGNYP

Interactive view

Cutaway side view (static)

Surface top view (static - coloured by atom property)

Cutaway top view (static)

Data provenance

MHC:peptide complexes are visualised using PyMol. The peptide is superimposed on a consistent cutaway slice of the MHC binding cleft (displayed as a grey mesh) which best indicates the binding pockets for the P1/P5/PC positions (side view - pockets A, E, F) and for the P2/P3/PC-2 positions (top view - pockets B, C, D). In some cases peptides will use a different pocket for a specific peptide position (atypical anchoring). On some structures the peptide may appear to sterically clash with a pocket. This is an artefact of picking a standardised slice of the cleft and overlaying the peptide.

Peptide neighbours

P1 GLY

LYS146

SER77

TRP73

THR143

TRP147

P2 LEU

LEU95

TRP73

TYR84

TYR123

ASN80

TRP147

PHE116

ILE124

LEU81

ILE142

LYS146

SER77

THR143

Colour key

Aromatic Hydrophobic Acidic Basic Neutral/polar

Data provenance

Neighbours are calculated by finding residues with atoms within 5Å of each other using BioPython Neighboursearch module. The list of neighbours is then sorted and filtered to inlcude only neighbours where between the peptide and the MHC Class I alpha chain.

Colours selected to match the YRB scheme. [https://www.frontiersin.org/articles/10.3389/fmolb.2015.00056/full]

Binding cleft pockets

Peptide sidechain binding pockets (static)

Peptide terminii and backbone binding residues (static)

A Pocket

TYR159

GLU163

TRP167

TYR171

MET5

TYR59

GLU63

LYS66

TYR7

B Pocket

SER24

VAL34

TYR45

GLU63

LYS66

ALA67

TYR7

GLN70

GLU9

SER99

C Pocket

GLN70

TRP73

PHE74

GLU9

GLN97

D Pocket

LEU114

HIS155

TYR156

TYR159

LEU160

SER99

E Pocket

LEU114

TRP147

ALA152

TYR156

GLN97

F Pocket

PHE116

TYR123

THR143

LYS146

TRP147

SER77

ASN80

LEU81

TYR84

LEU95

Colour key

Binds N-terminus Binds P1 backbone Binds P2 backbone Binds PC-1 backbone Binds C-terminus

Data provenance

N-/C-terminus and peptide backbone binding residues are assigned according to previously published information and pockets are assigned according to an adaptation of a previously published set of residues. All numbering is currently that of the 'canonical' structures of human and mouse MHC Class I molecules.

Chain sequences

1. Beta 2 microglobulin Beta 2 microglobulin	10 20 30 40 50 60 IQKTPQIQVYSRHPPENGKPNILNCYVTQFHPPHIEIQMLKNGKKIPKVEMSDMSFSKDW 70 80 90 SFYILAHTEFTPTETDTYACRVKHDSMAEPKTVYWDRDM

2. Class I alpha H2-Db	10 20 30 40 50 60 GPHSMRYFETAVSRPGLEEPRYISVGYVDNKEFVRFDSDAENPRYEPRAPWMEQEGPEYW 70 80 90 100 110 120 ERETQKAKGQEQWFRVSLRNLLGYYNQSAGGSHTLQQMSGCDLGSDWRLLRGYLQFAYEG 130 140 150 160 170 180 RDYIALNEDLKTWTAADMAAQITRRKWEQSGAAEHYKAYLEGECVEWLHRYLKNGNATLL 190 200 210 220 230 240 RTDSPKAHVTHHPRSKGEVTLRCWALGFYPADITLTWQLNGEELTQDMELVETRPAGDGT 250 260 270 280 290 300 FQKWASVVVPLGKEQNYTCRVYHEGLPEPLTLRWEPPPSTDSYMVIVAVLGVLGAMAIIG 310 320 330 AVVAFVMKRRRNTGGKGGDYALAPGSQSSEMSLRDCKA

3. Peptide	GL

Data provenance

Sequences are retrieved via the Uniprot method of the RSCB REST API. Sequences are then compared to those derived from the PDB file and matched against sequences retrieved from the IPD-IMGT/HLA database for human sequences, or the IPD-MHC database for other species. Mouse sequences are matched against FASTA files from Uniprot. Sequences for the mature extracellular protein (signal petide and cytoplasmic tail removed) are compared to identical length sequences from the datasources mentioned before using either exact matching or Levenshtein distance based matching.

Downloadable data

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Complete structures

Aligned structures [cif]

Components

MHC Class I alpha chain [cif]

MHC Class I antigen binding domain (alpha1/alpha2) [cif]

Peptide only [cif]

Derived data

Data for this page [json]

https://api.histo.fyi/v1/structures/6gb5

Data license

The data above is made available under a Creative Commons CC-BY 4.0 license. This means you can copy, remix, transform, build upon and redistribute the material, but you must give appropriate credit, provide a link to the license, and indicate if changes were made.

If you use any data downloaded from this site in a publication, please cite 'https://www.histo.fyi/'. A preprint is in preparation.

Footnotes

Protein Data Bank Europe - Coordinate Server
1HHK - HLA-A*02:01 binding LLFGYPVYV at 2.5Å resolution - PDB entry for 1HHK
Protein structure alignment by incremental combinatorial extension (CE) of the optimal path. - PyMol CEALIGN Method - Publication
PyMol - PyMol.org/pymol
Levenshtein distance - Wikipedia entry
Protein Data Bank Europe REST API - Molecules endpoint
3Dmol.js: molecular visualization with WebGL - 3DMol.js - Publication
Protein Data Bank Europe REST API - Publication endpoint
PubMed Central Europe REST API - Articles endpoint

This work is licensed under a Creative Commons Attribution 4.0 International License.