FB2026_03 , released September 17, 2026
Physical Interaction report
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General Information
Interaction Type
Interacting Genes
FlyBase ID
FBig0000101192
Interaction Network
Interactions Browser links
His3 network
pygo network
Reported Interactions
FBrf0204852-1.ITC
Description
physical association
Collection
Source/Stage
Cell line used
Participants
Corresponds to
Reported as
Role
Note
pygo 

dPHD

bait

GST tag

pygo 
His3 

H3

prey
His3 
His3 
Experimental entities
Corresponds to
Identifier
Reported
Role
Note
Subregions with role in interaction
Corresponds to
Description
Role
Coordinates
Note
pygo 
PHD domain
sufficient binding region
aa 747-808
His3 
H3 tail
sufficient binding region
aa 1-15
His3 
H3K4me2 site
necessary binding region
aa 4

dimethylated Lys4 residue

Isoform-specific participants
Corresponds to
Description
Role
Note
Comments concerning this interaction

Interaction in vitro; bait produced as a recombinant fusion protein in bacterial system; prey chemically synthesized.

pygo binds only to Lys4-methylated His3. The affinity of pygo PHD domain for the His3 tail when mono-, di- and trimethylated at Lys4 is 21.5 uM, 12.5 uM and 23 uM, respectively.

FBrf0208546-2.PD.WB
Description
physical association
Collection
Source/Stage
Cell line used
Participants
Corresponds to
Reported as
Role
Note
His3 

H3

bait

biotin tag

His3 
pygo 

dPygo

prey

GST tag

pygo 
pygo 
Experimental entities
Corresponds to
Identifier
Reported
Role
Note
Subregions with role in interaction
Corresponds to
Description
Role
Coordinates
Note
His3 
N-terminal domain
sufficient binding region
aa 1-21
pygo 
PHD domain
sufficient binding region
aa 739-815

coordinates relative to pygo-PA

pygo 
PHD domain residue 773
mutation increasing interaction
aa 773

F773W

Isoform-specific participants
Corresponds to
Description
Role
Note
Comments concerning this interaction

Interaction in vitro; bait peptides produced commercially; prey produced as a recombinant fusion protein in bacterial system.

The His3-pygo interaction occurs only when an lgs HD1 peptide, aa 315-348, is present or when F773 of pygo is mutated to W.

FBrf0223501-2.NMR
Description
physical association
Collection
Source/Stage
Cell line used
Participants
Corresponds to
Reported as
Role
Note
pygo 

Pygo

bait

[13]C-[15]N label

pygo 
His3 

H3

prey
His3 
His3 
His3 
Experimental entities
Corresponds to
Identifier
Reported
Role
Note
Subregions with role in interaction
Corresponds to
Description
Role
Coordinates
Note
pygo 
PHD domain
sufficient binding region
aa 747-808
His3 
H3 tail
sufficient binding region
aa 1-15
His3 
H3K4me2 site
necessary binding region
aa 4

dimethylated Lys4 residue

His3 
H3R2me2a site
binding-associated region
aa 2

asymmetrically methylated Arg2 residue

Isoform-specific participants
Corresponds to
Description
Role
Note
Comments concerning this interaction

Interaction in vitro; bait produced as a recombinant fusion proteins in bacterial system; prey chemically synthesized.

pygo binds more strongly to the His3 K4me2-modified tail if it also contains the R2me2a modification.

Chemical shifts in pygo residues upon His3 binding, molecular modeling and intermolecular nuclear Overhauser effects (NOEs) indicate that asymmetrically modified Arg2me2a of His3 binds the fly specific \'R2\' groove of the pygo PHD domain.

The pygo PHD domain was expressed as a fusion to the lgs HD1 domain, connected by a flexible linker.

FBrf0223501-3.ITC
Description
physical association
Collection
Source/Stage
Cell line used
Participants
Corresponds to
Reported as
Role
Note
pygo 

Pygo

bait
pygo 
pygo 
His3 

H3

prey
His3 
His3 
His3 
Experimental entities
Corresponds to
Identifier
Reported
Role
Note
Subregions with role in interaction
Corresponds to
Description
Role
Coordinates
Note
pygo 
PHD domain
sufficient binding region
aa 747-808
pygo 
PHD pocket divider
mutation increasing interaction
aa 773

F773W, \'humanized\' pygo

His3 
H3 tail
sufficient binding region
aa 1-15
His3 
H3K4me2 site
necessary binding region
aa 4

dimethylated Lys4 residue

His3 
H3R2me2a site
binding-associated region
aa 2

asymmetrically methylated Arg2 residue

Isoform-specific participants
Corresponds to
Description
Role
Note
Comments concerning this interaction

Interaction in vitro; bait produced as a recombinant fusion proteins in bacterial system; prey chemically synthesized.

pygo binds more strongly to the His3 K4me2-modified tail if it also contains the R2me2a modification.

Rendering fly pygo human-like by the F773W mutation increases its affinity for His3-K4me2 tail from 1 mM to 7.5 uM.

The pygo PHD domain was expressed as a fusion to the lgs HD1 domain, connected by a flexible linker.

External Crossreferences and Linkouts ( 0 )
References (3)