Table 1 The impact of PΩ-2 and PΩ peptide residue substitutions on HLA-peptide complex thermal stability

From: HLA-B57 micropolymorphism defines the sequence and conformational breadth of the immunopeptidome

Peptide sequence

HLA-B*57:01 Tm (°C)

PΩ-2 Q

PΩ W

X

HLA-B*57:03 Tm (°C)

PΩ-2 Q

PΩ W

X

HLA-B*58:01 Tm (°C)

PΩ-2 Q

PΩ W

X

LSSPVTKSF (wt)

70.6 (0.74)

−0. 2

2.0

 

69.2 (0.35)

0.4

1.8

 

69.3 (0.52)

0.9

2.5

 

LSSPVTQSF

70.4 (0.26)

–

2.7

 

69.6 (0.11)a

–

1.5

 

70.2 (0.7)

–

2.8

 

LSSPVTKSW

72.6 (0.41)

0.5

–

X

71.0 (0)

0.1

–

X

71.8 (0.61)

1.2

–

X

LSSPVTQSW

73.1 (0.18)a

–

–

 

71.1 (0.1)

–

–

 

73.0 (0.32)

–

–

 

LTVQVARVY (wt)

69.4 (0.18)a

−2.3

2.8

X

60.6 (0.67)

2.5

8.6

X

N.D.

–

–

 

LTVQVAQVY

67.1 (0.18)a

–

3.9

 

63.1 (0.14)

–

7.8

 

N.D.

–

–

 

LTVQVARVW

72.2 (0.46)

−1.2

–

X

69.2 (0.09)

1.7

–

X

67.8 (1.12)

4.6

–

X

LTVQVAQVW

71.0 (0.48)b

–

–

 

70.9 (0.19)

–

–

 

72.4 (0.61)c

–

–

 

SAAADETLRLW (wt)

67.5 (0.99)

–

–

 

61.3 (0.17)

–

–

 

64.4 (0.67)

–

–

 
  1. Thermal stability is reported as mean temperature for 50% unfold (Tm), standard deviation is shown in parentheses. Values are calculated from duplicates at 1 mg mL−1 protein and 0.5 mg mL−1 protein (4 total) unless indicated otherwise. The impact of the PΩ-2 to Q and PΩ to W on Tm are shown where applicable (‘–’ is placed where not applicable), changes of magnitude > 1 °C are underlined (decreased stability) or in bold (increased stability). Column X denotes complexes for which structures were solved using X-ray crystallography
  2. ND not determined due to poor HLA-peptide refold
  3. aValues calculated from duplicates at 0.5 mg mL−1 protein alone
  4. bValues calculated from duplicates at 0.8 and 0.5 mg mL−1 protein
  5. cValues calculated from quadruplicates at 1 and 0.5 mg mL−1 protein
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