Structural insights into the role of N-terminal integrity in PhoSL for core-fucosylated N-glycan recognition.

PhoSL (Pholiota squarrosa Lectin) has an exceptional binding affinity for biomolecules with core-fucosylated N-glycans. This modification involves the addition of fucose to the inner N-acetylglucosamine within the N-glycan structure and is known to influence many physiological processes. Nevertheless, the molecular interactions underlying high-affinity binding of native PhoSL to core-fucosylated N-glycans remain largely unknown.

Structural basis for promoter DNA recognition by the response regulator OmpR.

OmpR, a response regulator of the EnvZ/OmpR two-component system (TCS), controls the reciprocal regulation of two porin proteins, OmpF and OmpC, in bacteria. During signal transduction, OmpR (OmpR-FL) undergoes phosphorylation at its conserved Asp residue in the N-terminal receiver domain (OmpRn) and recognizes the promoter DNA from its C-terminal DNA-binding domain (OmpRc) to elicit an adaptive response. Apart from that, OmpR regulates many genes in Escherichia coli and is important for virulence in several pathogens.

Structural basis for -35 element recognition by σ chimera proteins and their interactions with PmrA response regulator.

In class II transcription activation, the transcription factor normally binds to the promoter near the -35 position and contacts the domain 4 of σ factors (σ ) to activate transcription. However, σ of σ appears to be poorly folded on its own. Here, by fusing σ with the RNA polymerase β-flap-tip-helix, we constructed two σ chimera proteins, one from σ and another from σ of Klebsiella pneumoniae.

Structural basis of interaction between dimeric cyclophilin 1 and Myb1 transcription factor in Trichomonas vaginalis.

Cyclophilin 1 (TvCyP1), a cyclophilin type peptidyl-prolyl isomerase present in the human parasite Trichomonas vaginalis, interacts with Myb1 and assists in its nuclear translocation. Myb1 regulates the expression of ap65-1 gene that encodes for a disease causing cytoadherence enzyme. Here, we determined the crystal structures of TvCyP1 and its complex with the minimum TvCyP1-binding sequence of Myb1 (Myb1), where TvCyP1 formed a homodimer, unlike other single domain cyclophilins.