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7P0A

H2-Db binding "KAPYNFATM" at 2.43Å 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.

Information sections


Complex type

Class i with peptide

1. Beta 2 microglobulin
['B', 'E']
2. Class I alpha
H2-Db
['A', 'D']
3. Peptide
KAPYNFATM
['C', 'F']

Species


Locus / Allele group


Publication

l- to d-Amino Acid Substitution in the Immunodominant LCMV-Derived Epitope gp33 Highlights the Sensitivity of the TCR Recognition Mechanism for the MHC/Peptide Structure and Dynamics.

Ballabio F, Broggini L, Paissoni C, Han X, Peqini K, Sala BM, Sun R, Sandalova T, Barbiroli A, Achour A, Pellegrino S, Ricagno S, Camilloni C
ACS Omega (2022) 7, 9622-9635 [doi:10.1021/acsomega.1c06964]  [pubmed:35350306

Presentation of pathogen-derived epitopes by major histocompatibility complex I (MHC-I) can lead to the activation and expansion of specific CD8+ T cell clones, eventually resulting in the destruction of infected target cells. Altered peptide ligands (APLs), designed to elicit immunogenicity toward a wild-type peptide, may affect the overall stability of MHC-I/peptide (pMHC) complexes and modulate the recognition by T cell receptors (TCR). Previous works have demonstrated that proline substitution at position 3 (p3P) of different MHC-restricted epitopes, including the immunodominant LCMV-derived epitope gp33 and escape variants, may be an effective design strategy to increase epitope immunogenicity. These studies hypothesized that the p3P substitution increases peptide rigidity, facilitating TCR binding. Here, molecular dynamics simulations indicate that the p3P modification rigidifies the APLs in solution predisposing them for the MHC-I loading as well as once bound to H-2Db, predisposing them for TCR binding. Our results also indicate that peptide position 6, key for interaction of H-2Db/gp33 with the TCR P14, takes a suboptimal conformation before as well as after binding to the TCR. Analyses of H-2Db in complex with APLs, in which position 6 was subjected to an l- to d-amino acid modification, revealed small conformational changes and comparable pMHC thermal stability. However, the l- to d-modification reduced significantly the binding to P14 even in the presence of the p3P modification. Our combined data highlight the sensitivity of the TCR for the conformational dynamics of pMHC and provide further tools to dissect and modulate TCR binding and immunogenicity via APLs.

Structure deposition and release

Deposited: 2021-06-29
Released: 2022-03-23
Revised: 2022-04-13

Data provenance

Publication data retrieved from PDBe REST API8 and PMCe REST API9

Other structures from this publication


Peptide details

Length: Nonamer (9 amino acids)

Sequence: KAPYNFATM

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 LYS

TYR171
TYR159
TYR59
ARG62
LYS66
TYR7
GLU163
GLU63
TRP167
MET5
P2 ALA

TYR7
GLU163
TYR45
LYS66
GLU63
TYR159
P3 PRO

GLU9
LYS66
SER99
TYR7
GLN70
TYR159
GLN97
P4 TYR

LYS66
GLN70
TYR156
HIS155
P5 ASN

PHE116
GLN70
TYR156
GLU9
HIS155
TRP73
PHE74
GLN97
P7 ALA

TYR156
TRP147
SER150
TRP73
P8 THR

TRP73
VAL76
THR143
TRP147
ASN80
SER77
P9 MET

SER77
TYR84
TYR123
LYS146
LEU95
TRP73
THR143
LEU81
ILE124
TRP147
ASN80
PHE116

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
MGIQKTPQIQVYSRHPPENGKPNILNCYVTQFHPPHIEIQMLKNGKKIPKVEMSDMSFSK
        70        80        90       100
DWSFYILAHTEFTPTETDTYACRVKHDSMAEPKTVYWDRDM

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
FQKWASVVVPLGKEQNYTCRVYHEGLPEPLTLRWEP

3. Peptide
KAPYNFATM


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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Please take note of the data license. Using data from this site assumes that you have read and will comply with the license.

Complete structures

Aligned structures [cif]
  1. 7P0A assembly 1  
  2. 7P0A assembly 2  

Components

MHC Class I alpha chain [cif]
  1. 7P0A assembly 1  
  2. 7P0A assembly 2  
MHC Class I antigen binding domain (alpha1/alpha2) [cif]
  1. 7P0A assembly 1  
  2. 7P0A assembly 2  
Peptide only [cif]
  1. 7P0A assembly 1  
  2. 7P0A assembly 2  

Derived data

Data for this page [json]
https://api.histo.fyi/v1/structures/7p0a

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