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Updated: Jul 12, 2026

Functional Complementation Analysis (FCA): A Laboratory Exercise Designed and Implemented to Supplement the Teaching of Biochemical Pathways
Published on: June 24, 2016
Cloning of genes for proline and leucine biosynthesis from Brucella abortus by functional complementation in
1Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater 74078.
Abstract:
By selecting for growth of Escherichia coli mutant strains in the absence of the required amino acid, clones were found in a Brucella abortus library carrying genes for glutamyl phosphate reductase (proA) and beta-isopropylmalate dehydrogenase (leuB). These clones hybridized to unique fragments in a genomic digest of B. abortus DNA. The proA-complementing DNA was found in a region of 1.3 kb, which directed the synthesis of a protein of 48,000 Da with a pI of 6.3 in maxicells. The leuB-complementing activity was in a region of 1.4 kb and directed synthesis of a protein of 46,000 Da with a pI of 5.9.

