Targeted Mutations of Bacillus anthracis Dihydrofolate Reductase Condense Complex Structure-Activity Relationships

Journal Article · Sat Dec 31 04:00:00 EST 2011 · Journal of Medicinal Chemistry

OSTI ID:1041704

Beierlein, J; Karri, N; Anderson, A

Several antifolates, including trimethoprim (TMP) and a series of propargyl-linked analogues, bind dihydrofolate reductase from Bacillus anthracis (BaDHFR) with lower affinity than is typical in other bacterial species. To guide lead optimization for BaDHFR, we explored a new approach to determine structure-activity relationships whereby the enzyme is altered and the analogues remain constant, essentially reversing the standard experimental design. Active site mutants of the enzyme, Ba(F96I)DHFR and Ba(Y102F)DHFR, were created and evaluated with enzyme inhibition assays and crystal structures. The affinities of the antifolates increase up to 60-fold with the Y102F mutant, suggesting that interactions with Tyr 102 are critical for affinity. Crystal structures of the enzymes bound to TMP and propargyl-linked inhibitors reveal the basis of TMP resistance and illuminate the influence of Tyr 102 on the lipophilic linker between the pyrimidine and aryl rings. Two new inhibitors test and validate these conclusions and show the value of the technique for providing new directions during lead optimization.

• Research Organization: BROOKHAVEN NATIONAL LABORATORY (BNL)
• Sponsoring Organization: USDOE SC OFFICE OF SCIENCE (SC)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1041704
• Report Number(s): BNL--97382-2012-JA
• Journal Information: Journal of Medicinal Chemistry, Journal Name: Journal of Medicinal Chemistry Journal Issue: 20 Vol. 53; ISSN JMCMAR; ISSN 0022-2623
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
60 APPLIED LIFE SCIENCES
AFFINITY
BACILLUS
CRYSTAL STRUCTURE
DESIGN
ENZYMES
MUTANTS
MUTATIONS
OPTIMIZATION
OXIDOREDUCTASES
PYRIMIDINES
STRUCTURE-ACTIVITY RELATIONSHIPS