PMID- 14753842
OWN - NLM
STAT- MEDLINE
DCOM- 20040409
LR  - 20171116
IS  - 0020-1669 (Print)
IS  - 0020-1669 (Linking)
VI  - 43
IP  - 3
DP  - 2004 Feb 9
TI  - Effect of equatorial ligands of dirhodium(II,II) complexes on the efficiency and 
      mechanism of transcription inhibition in vitro.
PG  - 1175-83
AB  - The nature of the equatorial ligands spanning the dirhodium core was shown to 
      affect the ability and mechanism of various lantern-type complexes to inhibit 
      transcription in vitro. The inhibition of transcription by 
      Rh(2)(mu-O(2)CCF(3))(4), Rh(2)(mu-HNCOCF(3))(4), and 
      [Rh(2)(mu-O(2)CCH(3))(2)(CH(3)CN)(6)](2+) appears to proceed predominantly via 
      binding of the complexes to T7-RNA polymerase (T7-RNAP) and is dependent on the 
      concentration of enzyme and Mg(2+) ions in solution. The concentrations of the 
      aforementioned complexes required to inhibit 50% of the transcription, 
      C(inh)(50), are similar to that measured for activated cisplatin, whereas a 
      significantly higher concentration of Rh(2)(mu-HNCOCH(3))(4) is required to 
      effect similar inhibition; the inhibition induced by Rh(2)(mu-HNCOCH(3))(4) does 
      not involve binding to T7-RNAP. The spectral changes observed for each complex 
      upon addition of enzyme are consistent with Rh(2)(mu-O(2)CCF(3))(4), 
      Rh(2)(mu-HNCOCF(3))(4), and [Rh(2)(mu-O(2)CCH(3))(2)(CH(3)CN)(6)](2+) binding to 
      the enzyme and may involve partial displacement of the equatorial (eq) groups by 
      the Lewis basic sites of T7-RNAP. In contrast, addition of enzyme to solutions of 
      Rh(2)(mu-HNCOCH(3))(4) does not result in significant spectral changes, a finding 
      consistent with lack of enzyme dependence in the transcription inhibition. These 
      differences in reactivity and transcription inhibition mechanism among complexes 
      with different bridging ligands are explained by variations of the Lewis acidity 
      of the axial (ax) sites in the series of complexes Rh(2)(mu-O(2)CCF(3))(4), 
      Rh(2)(mu-HNCOCF(3))(4), and Rh(2)(mu-HNCOCH(3))(4). The Lewis acidity of the ax 
      sites is expected to affect the initial interaction of the complexes with the 
      biomolecules, followed by their rearrangement to eq positions if the bridging 
      ligands are labile.
FAU - Chifotides, Helen T
AU  - Chifotides HT
AD  - Department of Chemistry, The Ohio State University, Columbus, Ohio 43210, USA.
FAU - Fu, Patty K-L
AU  - Fu PK
FAU - Dunbar, Kim R
AU  - Dunbar KR
FAU - Turro, Claudia
AU  - Turro C
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Inorg Chem
JT  - Inorganic chemistry
JID - 0366543
RN  - 0 (Antineoplastic Agents)
RN  - 0 (Ligands)
RN  - 0 (Organometallic Compounds)
RN  - 0 (RNA, Messenger)
RN  - 27432CM55Q (Serum Albumin, Bovine)
RN  - DMK383DSAC (Rhodium)
RN  - EC 2.7.7.6 (DNA-Directed RNA Polymerases)
RN  - I38ZP9992A (Magnesium)
RN  - Q20Q21Q62J (Cisplatin)
SB  - IM
MH  - Antineoplastic Agents/pharmacology
MH  - Bacteriophage T7/enzymology
MH  - Cisplatin/pharmacology
MH  - DNA-Directed RNA Polymerases/antagonists & inhibitors
MH  - Ligands
MH  - Magnesium/chemistry
MH  - Organometallic Compounds/chemical synthesis/*chemistry/*pharmacology
MH  - RNA, Messenger/biosynthesis/drug effects/genetics
MH  - Rhodium/*chemistry/*pharmacology
MH  - Serum Albumin, Bovine/chemistry
MH  - Spectrophotometry, Ultraviolet
MH  - Transcription, Genetic/*drug effects
EDAT- 2004/02/03 05:00
MHDA- 2004/04/10 05:00
CRDT- 2004/02/03 05:00
PHST- 2004/02/03 05:00 [pubmed]
PHST- 2004/04/10 05:00 [medline]
PHST- 2004/02/03 05:00 [entrez]
AID - 10.1021/ic034438m [doi]
PST - ppublish
SO  - Inorg Chem. 2004 Feb 9;43(3):1175-83. doi: 10.1021/ic034438m.