11B NMR spectroscopy of peptide boronic acid inhibitor complexes of alpha-lytic protease. Direct evidence for tetrahedral boron in both boron-histidine and boron-serine adduct complexes.
We have previously shown, using 15N and 1H NMR spectroscopy, that MeOSuc-Ala-Ala-Pro-boroPhe and certain other boronic acid inhibitors form boron-histidine adducts with alpha-lytic protease instead of transition-state-like tetrahedral boron-serine adducts as is generally supposed [Bachovchin, W. W., Wong, W. Y. L., Farr-Jones, S., Shenvi, A. B., & Kettner, C. (1988) Biochemistry 27, 7689-7697]. An X-ray crystallographic study of the MeOSuc-Ala-Ala-Pro-boroPhe complex with alpha-lytic protease [Bone, R., Frank, D., Kettner, C. A., & Agard, D. A. (1989) Biochemistry 28, 7600-7609] has confirmed the existence of the boron-histidine bond but has concluded that the boron atom is trigonal rather than tetrahedral. Here we report a 11B NMR study at 160.46 MHz of this histidine adduct complex and of two other complexes known to be serine adducts: alpha-lytic protease with MeOSuc-Ala-Ala-Pro-boroVal and chymotrypsin with MeOSucAla-Ala-Pro-boroPhe. The 11B NMR chemical shifts demonstrate that the boron atom is tetrahedral in both the histidine and serine adduct complexes.(ABSTRACT TRUNCATED AT 250 WORDS)
Tsilikounas
E
E
Department of Biochemistry, Tufts University School of Medicine, Boston, Massachusetts 02111.
Kettner
C A
CA
Bachovchin
W W
WW
D000595:Amino Acid Sequence; D001895:Boron / Q000737:chemistry*; D001897:Boronic Acids / Q000737:chemistry*; D002918:Chymotrypsin / Q000737:chemistry; D006090:Gram-Negative Bacteria / Q000201:enzymology; D006639:Histidine / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry*; D012694:Serine / Q000737:chemistry; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000378:metabolism
D001897:Boronic Acids; D009842:Oligopeptides; D012694:Serine; D006639:Histidine; C084716:O-methyl-succinyl-alanyl-alanyl-prolyl-borovaline; C084717:O-methylsuccinyl-alanyl-alanyl-prolyl-borophenylalanine; D012697:Serine Endopeptidases; D002918:Chymotrypsin; C021826:myxobacter alpha-lytic proteinase; D001895:Boron