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1VAC

H2-Kb binding "SIINFEKL" at 2.50Å 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']
2. Class I alpha
H2-Kb
['A']
3. Peptide
SIINFEKL
['P']

Species


Locus / Allele group


Publication

Crystal structure of an H-2Kb-ovalbumin peptide complex reveals the interplay of primary and secondary anchor positions in the major histocompatibility complex binding groove.

Fremont DH, Stura EA, Matsumura M, Peterson PA, Wilson IA
Proc. Natl. Acad. Sci. U.S.A. (1995) 92, 2479-83 [doi:10.1073/pnas.92.7.2479]  [pubmed:7708669

Sequence analysis of peptides naturally presented by major histocompatibility complex (MHC) class I molecules has revealed allele-specific motifs in which the peptide length and the residues observed at certain positions are restricted. Nevertheless, peptides containing the standard motif often fail to bind with high affinity or form physiologically stable complexes. Here we present the crystal structure of a well-characterized antigenic peptide from ovalbumin [OVA-8, ovalbumin-(257-264), SIINFEKL] in complex with the murine MHC class I H-2Kb molecule at 2.5-A resolution. Hydrophobic peptide residues Ile-P2 and Phe-P5 are packed closely together into binding pockets B and C, suggesting that the interplay of peptide anchor (P5) and secondary anchor (P2) residues can couple the preferred sequences at these positions. Comparison with the crystal structures of H-2Kb in complex with peptides VSV-8 (RGYVYQGL) and SEV-9 (FAPGNYPAL), where a Tyr residue is used as the C pocket anchor, reveals that the conserved water molecule that binds into the B pocket and mediates hydrogen bonding from the buried anchor hydroxyl group could not be likewise positioned if the P2 side chain were of significant size. Based on this structural evidence, H-2Kb has at least two submotifs: one with Tyr at P5 (or P6 for nonamer peptides) and a small residue at P2 (i.e., Ala or Gly) and another with Phe at P5 and a medium-sized hydrophobic residue at P2 (i.e., Ile). Deciphering of these secondary submotifs from both crystallographic and immunological studies of MHC peptide binding should increase the accuracy of T-cell epitope prediction.

Structure deposition and release

Deposited: 1994-11-01
Released: 1996-06-20
Revised: 2011-07-13

Data provenance

Publication data retrieved from PDBe REST API8 and PMCe REST API9

Other structures from this publication


Peptide details

Length: Octamer (8 amino acids)

Sequence: SIINFEKL

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 SER

TYR159
TYR59
LYS66
TRP167
TYR171
TYR7
GLU63
LEU5
P2 ILE

TYR7
TYR159
VAL9
LYS66
GLU63
ASN70
TYR45
GLU24
P3 ILE

TYR159
ARG155
SER99
LYS66
GLN114
ASN70
LEU156
P4 ASN

ASN70
ARG155
LYS66
P5 PHE

PHE74
GLU24
VAL97
TYR116
TYR22
ARG155
SER73
SER99
VAL9
GLN114
ASN70
P6 GLU

SER73
ASP77
GLU152
ARG155
TYR116
TRP147
P7 LYS

ASP77
LYS146
VAL76
TRP147
SER73
P8 LEU

ILE124
TYR84
TYR123
LYS146
ILE95
THR143
TRP147
ASP77
THR80
TYR116
LEU81

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
THR163
TRP167
TYR171
LEU5
TYR59
GLU63
LYS66
TYR7
B Pocket

GLU24
VAL34
TYR45
GLU63
LYS66
ALA67
TYR7
ASN70
VAL9
SER99
C Pocket

ASN70
SER73
PHE74
VAL9
VAL97
D Pocket

GLN114
ARG155
LEU156
TYR159
LEU160
SER99
E Pocket

GLN114
TRP147
GLU152
LEU156
VAL97
F Pocket

TYR116
TYR123
THR143
LYS146
TRP147
ASP77
THR80
LEU81
TYR84
ILE95

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-Kb
        10        20        30        40        50        60
GPHSLRYFVTAVSRPGLGEPRYMEVGYVDDTEFVRFDSDAENPRYEPRARWMEQEGPEYW
        70        80        90       100       110       120
ERETQKAKGNEQSFRVDLRTLLGYYNQSKGGSHTIQVISGCEVGSDGRLLRGYQQYAYDG
       130       140       150       160       170       180
CDYIALNEDLKTWTAADMAALITKHKWEQAGEAERLRAYLEGTCVEWLRRYLKNGNATLL
       190       200       210       220       230       240
RTDSPKAHVTHHSRPEDKVTLRCWALGFYPADITLTWQLNGEELIQDMELVETRPAGDGT
       250       260       270
FQKWASVVVPLGKEQYYTCHVYHQGLPEPLTLRW

3. Peptide
SIINFEKL


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]
  1. 1VAC assembly 1  

Components

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

Derived data

Data for this page [json]
https://api.histo.fyi/v1/structures/1vac

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