BDP4

BDP4 (PF3D7_1475600) is a putative bromodomain-containing epigenetic reader protein in Plasmodium falciparum. It was identified through histone peptide pull-down as one of 14 candidate reader proteins that associate with histone post-translational modification marks, and interaction proteomics placed it within one of the parasite's five major epigenetic complexes (PMID:31728527). Its bromodomain (PfBDP4-BRD) forms a defined, ligand-accessible binding pocket: a stabilized surrogate construct enabled a 1.25 Å co-crystal structure with a small-molecule inhibitor, confirming that the domain is druggable and binds ligand within its pocket (PMID:42068230). Beyond its identification as a histone-mark-associated reader, its complex membership, and the structural characterization of its bromodomain, no further mechanistic detail — including specific histone marks read, complex partners, or cellular function — has been characterized in the available corpus.

1. 2019 Medium

   Establishing whether PF3D7_1475600 functions as a chromatin reader answered the basic question of its molecular role, placing it among the parasite's histone-mark-recognizing proteins and within an epigenetic complex.

   Evidence Histone peptide pull-down (quantitative proteomics) plus interaction proteomics (tagging + AP-MS) in P. falciparum

   PMID:31728527

   Open questions at the time

   • The specific histone post-translational modification mark(s) recognized by BDP4 are not defined
   • The identity of the co-complex partners for BDP4 specifically is not elaborated
   • The cellular or developmental function of BDP4 is not established
2. 2026 High

   Determining whether the BDP4 bromodomain is a tractable ligand-binding module answered whether the reader domain forms a defined druggable pocket, providing an atomic-resolution structural framework and demonstrating small-molecule engagement.

   Evidence ProteinMPNN-guided surrogate design, virtual screening, ITC, and X-ray co-crystallography at 1.25 Å in P. falciparum

   PMID:42068230

   Open questions at the time

   • The native (non-surrogate) bromodomain structure and its endogenous histone-peptide ligand were not resolved
   • No cellular consequence of inhibitor binding on BDP4 function was tested
   • Whether small-molecule occupancy displaces a physiological histone-mark ligand is unknown

• The physiological role of BDP4 — which histone marks it reads, its precise complex composition, and its function in parasite gene regulation or development — remains unresolved.
• No genetic loss-of-function or knockdown phenotype for BDP4 is reported in the corpus
• No defined endogenous histone-mark specificity
• No functional link between bromodomain ligand binding and a downstream parasite process