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Selective Affimers Recognise the BCL‐2 Family Proteins BCL‐x L and MCL‐1 through Noncanonical Structural Motifs **
Author(s) -
Miles Jennifer A.,
Hobor Fruzsina,
Trinh Chi H.,
Taylor James,
Tiede Christian,
Rowell Philip R.,
Jackson Brian R.,
Nadat Fatima A.,
Ramsahye Pallavi,
Kyle Hannah F.,
Wicky Basile I. M.,
Clarke Jane,
Tomlinson Darren C.,
Wilson Andrew J.,
Edwards Thomas A.
Publication year - 2021
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.202000585
Subject(s) - bcl 2 family , biology , phage display , protein design , bcl xl , protein family , computational biology , template , protein–protein interaction , plasma protein binding , microbiology and biotechnology , protein structure , chemistry , biochemistry , apoptosis , programmed cell death , peptide , nanotechnology , gene , materials science
Abstract : The BCL‐2 family is a challenging group of proteins to target selectively due to sequence and structural homologies across the family. Selective ligands for the BCL‐2 family regulators of apoptosis are useful as probes to understand cell biology and apoptotic signalling pathways, and as starting points for inhibitor design. We have used phage display to isolate Affimer reagents (non‐antibody‐binding proteins based on a conserved scaffold) to identify ligands for MCL‐1, BCL‐x L , BCL‐2, BAK and BAX, then used multiple biophysical characterisation methods to probe the interactions. We established that purified Affimers elicit selective recognition of their target BCL‐2 protein. For anti‐apoptotic targets BCL‐x L and MCL‐1, competitive inhibition of their canonical protein‐protein interactions is demonstrated. Co‐crystal structures reveal an unprecedented mode of molecular recognition; where a BH3 helix is normally bound, flexible loops from the Affimer dock into the BH3 binding cleft. Moreover, the Affimers induce a change in the target proteins towards a desirable drug‐bound‐like conformation. These proof‐of‐concept studies indicate that Affimers could be used as alternative templates to inspire the design of selective BCL‐2 family modulators and more generally other protein‐protein interaction inhibitors.