Crystal Structure of the Human TAF4-TAF12 (TAFII135-TAFII20) Complex

Crystal Structure of a Subcomplex of Human Transcription Factor TFIID Formed by TATA Binding Protein-Associated Factors Htaf4 (Htaf(II)135) and Htaf12 (Htaf(II)20).

The Human TFIID Components Tafii135 and Tafii20 and the Yeast Saga Components Ada1 and Tafii68 Heterodimerize to Form Histone-Like Pairs

N-TERMINAL SELENOMETHIONINE INSERT, UNIFORM SELENO-METHIONINE LABELING
TRANSCRIPTION INITIATION FACTOR TFIID 135 KDA SUBUNIT

RESIDUES (GLY SER HIS MSE) INSERTED AT THE N-TERMINUS, REMAINDER OF HISTIDINE-TAG AFTER THROMBIN TREATMENT, UNIFORM SELENO-METHIONINE LABELING
TRANSCRIPTION INITIATION FACTOR TFIID 20/15 KDA SUBUNITS

TAFII-135, TAFII135, TAFII-130, TAFII130, TAF4A, TAF2C, HTAF4

TAFII-20/TAFII-15, TAFII20/TAFII15, TAF12, TAF2J

GSH(MSE)VLTKKKLQDLVREVDPNEQLDEDVEE(MSE)LLQIADDFIESVVTAACQLARHRKSSTLEVKDVQLHLERQW
N(MSE)WI

DATA QUALITY STATISTICS LISTED PERTAIN TO REMOTE WAVELENGTH DATA (0.90730 A)

HTAF4:
MULTIMERIC PROTEIN COMPLEX THAT PLAYS A CENTRAL ROLE IN MEDIATING
PROMOTER RESPONSES TO VARIOUS ACTIVATORS AND REPRESSORS.

HTAF12:
BELONGS TO THE TAF2J FAMILY. MAKES INTERACTIONS WITH TBP.
TWO ISOFORMS PRODUCED BY ALTERNATIVE INITIATION.

HTAF4: CONTAINS A SELENOMETHIONINE INSERTION AT N-TERMINUS
MSE 869 CHAINS A AND C.

HTAF12: CONTAINS A 4 RESIDUE INSERTION (GLY SER HIS MSE)
AT N-TERMINUS RESIDUES 53-56 CHAINS B AND D.

ENGINEERED DELETION MUTANT

THE HTAF12 POLYPEPTIDE THAT WAS USED FOR CRYSTALLIZATION
CONTAINED THE SEQUENCE GLY-SER-HIS-MET
(ORIGINATING FROM THE EXPRESSION PLASMID) AT ITS N
TERMINUS. NO ELECTRON DENSITY WAS SEEN FOR THE FIRST TWO OF
THESE RESIDUES (GLY-SER, NOT PRESENT IN THE MODEL), WHEREAS
THE THIRD (HIS) HAS BEEN REPLACED BY ALA IN THE MODEL
(NO DENSITY WAS SEEN FOR ITS SIDE CHAIN).

NO ELECTRON DENSITY WAS OBSERVED FOR THE C-TERMINAL PORTION OF HTAF4, RESIDUES 918-943, WHICH IS THEREFORE ABSENT FROM THE MODEL. THE FACT THAT PART OF THE PROTEIN COMPLEX DID NOT SHOW UP IN ELECTRON DENSITY MAPS WAS NOT DUE TO PROTEOLYSIS (AS EVIDENCED BY MASS SPECTROSCOPY OF REDISSOLVED CRYSTALS), INDICATING THAT THE REGIONS INVOLVED ARE DISORDERED WITHIN THE CRYSTAL LATTICE.

TWO HETERODIMERS FORMED BY CHAINS A AND B , OR CHAINSC AND D.

TRANSCRIPTION/TBP-ASSOCIATED FACTORS, TBP-ASSOCIATED FACTORS, TFIID, RNA POLYMERASE II TRANSCRIPTION, HISTONE FOLD DOMAINS, NUCLEAR PROTEIN, TRANSCRIPTION-TBP-ASSOCIATED FACTORS complex