PMID- 20014435
OWN - NLM
STAT- MEDLINE
DCOM- 20100520
LR  - 20211020
IS  - 1469-896X (Electronic)
IS  - 0961-8368 (Print)
IS  - 0961-8368 (Linking)
VI  - 19
IP  - 3
DP  - 2010 Mar
TI  - Characterization of site-directed mutants of residues R58, R59, D116, W340 and 
      R372 in the active site of E. coli cystathionine beta-lyase.
PG  - 383-91
LID - 10.1002/pro.308 [doi]
AB  - Cystathionine beta-lyase (CBL) catalyzes the hydrolysis of L-cystathionine 
      (L-Cth) to produce L-homocysteine, pyruvate, and ammonia. A series of active-site 
      mutants of Escherichia coli CBL (eCBL) was constructed to investigate the roles 
      of residues R58, R59, D116, W340, and R372 in catalysis and inhibition by 
      aminoethoxyvinylglycine (AVG). The effects of these mutations on the k(cat)/K(m) 
      (L-Cth) for the beta-elimination reaction range from a reduction of only 3-fold 
      for D116A and D116N to 6 orders of magnitude for the R372L and R372A mutants. The 
      order of importance of these residues for the hydrolysis of L-Cth is: R372 >> R58 
      > W340 approximately R59 > D116. Comparison of the kinetic parameters for L-Cth 
      hydrolysis with those for inhibition of eCBL by AVG demonstrates that residue R58 
      tethers the distal carboxylate group of the substrate and confirms that residues 
      W340 and R372 interact with the alpha-carboxylate moiety. The increase in the 
      pK(a) of the acidic limb and decrease in the pK(a) of the basic limb of the 
      k(cat)/K(m) (L-Cth) versus pH profiles of the R58K and R58A mutants, 
      respectively, support a role for this residue in modulating the pK(a) of an 
      active-site residue.
FAU - Lodha, Pratik H
AU  - Lodha PH
AD  - Department of Biology, Carleton University, Ottawa K1S 5B6, Canada.
FAU - Jaworski, Allison F
AU  - Jaworski AF
FAU - Aitken, Susan M
AU  - Aitken SM
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Protein Sci
JT  - Protein science : a publication of the Protein Society
JID - 9211750
RN  - 0 (Enzyme Inhibitors)
RN  - 30KYC7MIAI (Aspartic Acid)
RN  - 375YFJ481O (Cystathionine)
RN  - 8DUH1N11BX (Tryptophan)
RN  - 94ZLA3W45F (Arginine)
RN  - EC 4.- (Lyases)
RN  - EC 4.4.1.8 (cystathionine beta-lyase)
RN  - OW5H814Y1I (aminoethoxyvinylglycine)
RN  - TE7660XO1C (Glycine)
SB  - IM
MH  - Arginine/genetics/metabolism
MH  - Aspartic Acid/genetics/metabolism
MH  - Catalysis
MH  - Catalytic Domain/genetics
MH  - Cystathionine/*metabolism
MH  - Enzyme Inhibitors/pharmacology
MH  - Escherichia coli/*enzymology
MH  - Glycine/analogs & derivatives/pharmacology
MH  - Hydrolysis
MH  - Lyases/antagonists & inhibitors/genetics/*metabolism
MH  - Mutagenesis, Site-Directed
MH  - Tryptophan/genetics/metabolism
PMC - PMC2866265
EDAT- 2009/12/17 06:00
MHDA- 2010/05/21 06:00
PMCR- 2011/03/01
CRDT- 2009/12/17 06:00
PHST- 2009/12/17 06:00 [entrez]
PHST- 2009/12/17 06:00 [pubmed]
PHST- 2010/05/21 06:00 [medline]
PHST- 2011/03/01 00:00 [pmc-release]
AID - 10.1002/pro.308 [doi]
PST - ppublish
SO  - Protein Sci. 2010 Mar;19(3):383-91. doi: 10.1002/pro.308.