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Interaction pattern of Arg 62 in the A-pocket of differentially disease-associated HLA-B27 subtypes suggests distinct TCR binding modes.

Nurzia E, Narzi D, Cauli A, Mathieu A, Tedeschi V, Caristi S, Sorrentino R, Böckmann RA, Fiorillo MT - PLoS ONE (2012)

Bottom Line: Simulations of HLA:peptide systems suggest that peptide-stabilizing interactions of the Arg62 residue observed in crystal structures are metastable for both B27 subtypes under physiological conditions, rendering this arginine solvent-exposed and, probably, a key residue for TCR interaction more than peptide-binding.This view is supported by functional experiments with conservative (R62K) and non-conservative (R62A) B*2705 and B*2709 mutants that showed an overall reduction in their capability to present peptides to CD8+ T cells.Moreover, major subtype-dependent differences in the peptide recognition suggest distinct TCR binding modes for the B*2705 versus the B*2709 subtype.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology and Biotechnology C Darwin, Sapienza University, Rome, Italy.

ABSTRACT
The single amino acid replacement Asp116His distinguishes the two subtypes HLA-B*2705 and HLA-B*2709 which are, respectively, associated and non-associated with Ankylosing Spondylitis, an autoimmune chronic inflammatory disease. The reason for this differential association is so far poorly understood and might be related to subtype-specific HLA:peptide conformations as well as to subtype/peptide-dependent dynamical properties on the nanoscale. Here, we combine functional experiments with extensive molecular dynamics simulations to investigate the molecular dynamics and function of the conserved Arg62 of the α1-helix for both B27 subtypes in complex with the self-peptides pVIPR (RRKWRRWHL) and TIS (RRLPIFSRL), and the viral peptides pLMP2 (RRRWRRLTV) and NPflu (SRYWAIRTR). Simulations of HLA:peptide systems suggest that peptide-stabilizing interactions of the Arg62 residue observed in crystal structures are metastable for both B27 subtypes under physiological conditions, rendering this arginine solvent-exposed and, probably, a key residue for TCR interaction more than peptide-binding. This view is supported by functional experiments with conservative (R62K) and non-conservative (R62A) B*2705 and B*2709 mutants that showed an overall reduction in their capability to present peptides to CD8+ T cells. Moreover, major subtype-dependent differences in the peptide recognition suggest distinct TCR binding modes for the B*2705 versus the B*2709 subtype.

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CTL reactivity against pLMP2 bound to R62K and R62A B*2705/09 mutants and wt molecules.pLMP2-driven CTL lines derived from a B*2705 positive patients with AS (PIC) and two B*2709 positive individual (DE and PMC) have been tested in a 4 h standard 51chromium-release assay using HeLa transfectants expressing wt or mutants of B*2705 and B*2709 subtypes as target cells after ON treatment with pLMP2 (70 µM) or in absence of peptide. Effector/target ratio was 15∶1. Mean percentage of lysis ± SD of three separate experiments is shown here.
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pone-0032865-g005: CTL reactivity against pLMP2 bound to R62K and R62A B*2705/09 mutants and wt molecules.pLMP2-driven CTL lines derived from a B*2705 positive patients with AS (PIC) and two B*2709 positive individual (DE and PMC) have been tested in a 4 h standard 51chromium-release assay using HeLa transfectants expressing wt or mutants of B*2705 and B*2709 subtypes as target cells after ON treatment with pLMP2 (70 µM) or in absence of peptide. Effector/target ratio was 15∶1. Mean percentage of lysis ± SD of three separate experiments is shown here.

Mentions: As for the recognition of pLMP2, we tested four CTL lines: two from a B*2705 patient with AS (PIC) and two from two different B*2709 individuals (DE and PMC). PIC3 and PIC5 CTL lines behaved similarly showing reduced lytic activity against both B*2705 and B*2709 mutant HeLa cells incubated with pLMP2 in comparison with the wt molecules (Fig. 5). Interestingly, pLMP2 was recognized slightly better when presented by the conservative mutant in B*2705 context vs the non-conservative one, while the opposite occurred in the B*2709 context. DE5 displayed only a negligible recognition of pLMP2 on mutant R62K B*2705 and the same trend of PIC3 and PIC5 with the B*2709 mutants. The CTL line PMC6 tested only in the B*2705 context, showed lack of reactivity towards pLMP2 on both mutants. No CTL line, either pVIPR- or pLMP2- specific, was able to lyse untransfected HeLa cells incubated with the relevant peptide (data not shown).


Interaction pattern of Arg 62 in the A-pocket of differentially disease-associated HLA-B27 subtypes suggests distinct TCR binding modes.

Nurzia E, Narzi D, Cauli A, Mathieu A, Tedeschi V, Caristi S, Sorrentino R, Böckmann RA, Fiorillo MT - PLoS ONE (2012)

CTL reactivity against pLMP2 bound to R62K and R62A B*2705/09 mutants and wt molecules.pLMP2-driven CTL lines derived from a B*2705 positive patients with AS (PIC) and two B*2709 positive individual (DE and PMC) have been tested in a 4 h standard 51chromium-release assay using HeLa transfectants expressing wt or mutants of B*2705 and B*2709 subtypes as target cells after ON treatment with pLMP2 (70 µM) or in absence of peptide. Effector/target ratio was 15∶1. Mean percentage of lysis ± SD of three separate experiments is shown here.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3293911&req=5

pone-0032865-g005: CTL reactivity against pLMP2 bound to R62K and R62A B*2705/09 mutants and wt molecules.pLMP2-driven CTL lines derived from a B*2705 positive patients with AS (PIC) and two B*2709 positive individual (DE and PMC) have been tested in a 4 h standard 51chromium-release assay using HeLa transfectants expressing wt or mutants of B*2705 and B*2709 subtypes as target cells after ON treatment with pLMP2 (70 µM) or in absence of peptide. Effector/target ratio was 15∶1. Mean percentage of lysis ± SD of three separate experiments is shown here.
Mentions: As for the recognition of pLMP2, we tested four CTL lines: two from a B*2705 patient with AS (PIC) and two from two different B*2709 individuals (DE and PMC). PIC3 and PIC5 CTL lines behaved similarly showing reduced lytic activity against both B*2705 and B*2709 mutant HeLa cells incubated with pLMP2 in comparison with the wt molecules (Fig. 5). Interestingly, pLMP2 was recognized slightly better when presented by the conservative mutant in B*2705 context vs the non-conservative one, while the opposite occurred in the B*2709 context. DE5 displayed only a negligible recognition of pLMP2 on mutant R62K B*2705 and the same trend of PIC3 and PIC5 with the B*2709 mutants. The CTL line PMC6 tested only in the B*2705 context, showed lack of reactivity towards pLMP2 on both mutants. No CTL line, either pVIPR- or pLMP2- specific, was able to lyse untransfected HeLa cells incubated with the relevant peptide (data not shown).

Bottom Line: Simulations of HLA:peptide systems suggest that peptide-stabilizing interactions of the Arg62 residue observed in crystal structures are metastable for both B27 subtypes under physiological conditions, rendering this arginine solvent-exposed and, probably, a key residue for TCR interaction more than peptide-binding.This view is supported by functional experiments with conservative (R62K) and non-conservative (R62A) B*2705 and B*2709 mutants that showed an overall reduction in their capability to present peptides to CD8+ T cells.Moreover, major subtype-dependent differences in the peptide recognition suggest distinct TCR binding modes for the B*2705 versus the B*2709 subtype.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology and Biotechnology C Darwin, Sapienza University, Rome, Italy.

ABSTRACT
The single amino acid replacement Asp116His distinguishes the two subtypes HLA-B*2705 and HLA-B*2709 which are, respectively, associated and non-associated with Ankylosing Spondylitis, an autoimmune chronic inflammatory disease. The reason for this differential association is so far poorly understood and might be related to subtype-specific HLA:peptide conformations as well as to subtype/peptide-dependent dynamical properties on the nanoscale. Here, we combine functional experiments with extensive molecular dynamics simulations to investigate the molecular dynamics and function of the conserved Arg62 of the α1-helix for both B27 subtypes in complex with the self-peptides pVIPR (RRKWRRWHL) and TIS (RRLPIFSRL), and the viral peptides pLMP2 (RRRWRRLTV) and NPflu (SRYWAIRTR). Simulations of HLA:peptide systems suggest that peptide-stabilizing interactions of the Arg62 residue observed in crystal structures are metastable for both B27 subtypes under physiological conditions, rendering this arginine solvent-exposed and, probably, a key residue for TCR interaction more than peptide-binding. This view is supported by functional experiments with conservative (R62K) and non-conservative (R62A) B*2705 and B*2709 mutants that showed an overall reduction in their capability to present peptides to CD8+ T cells. Moreover, major subtype-dependent differences in the peptide recognition suggest distinct TCR binding modes for the B*2705 versus the B*2709 subtype.

Show MeSH
Related in: MedlinePlus