Structure of a Specific Acyl-Enzyme Complex formed between ß-Casomorphin-7 and Porcine Pancreatic Elastase

RC Wilmouth; IJ Clifton; CV Robinson; PL Roach; RT Aplin; Nicholas James Westwood; J Hajdu; CJ Schofield

Structure of a Specific Acyl-Enzyme Complex formed between ß-Casomorphin-7 and Porcine Pancreatic Elastase

RC Wilmouth, IJ Clifton, CV Robinson, PL Roach, RT Aplin, Nicholas James Westwood, J Hajdu, CJ Schofield

Research output: Other contribution

Abstract

Mass spectrometric screening reveals that an unmodified natural heptapeptide-human beta-casomorphin-7, an internal sequence of human beta-casein that possesses opioid-like activity-reacts with porcine pancreatic elastase to form an unusually stable acyl-enzyme complex at low pH. X-ray crystallographic analysis (to 1.9 Angstrom resolution) at pH 5 shows continuous electron density linking the C-terminal isoleucine of beta-casomorphin-7 to Ser 195 through an ester bond. The structure reveals a well defined water molecule (Wat 317), equidistant between the carbon of the ester carbonyl and N epsilon 2 of His 57. Deprotonation of Wat 317 will produce a hydroxide ion positioned to attack the ester carbonyl through the favoured Burgi-Dunitz trajectory.

Original language	English
Volume	4
Publication status	Published - Jun 1997

Keywords

ELECTROSPRAY MASS-SPECTROMETRY
CATALYTIC WATER MOLECULE
GAMMA-CHYMOTRYPSIN
SUBSTRATE-SPECIFICITY
ALPHA-CHYMOTRYPSIN
SERINE PROTEASES
HUMAN-LEUKOCYTE
MECHANISM
INTERMEDIATE
INHIBITORS

Cite this

@misc{2b56d8dfb95c40ff8839ae939f4b6556,

title = "Structure of a Specific Acyl-Enzyme Complex formed between {\ss}-Casomorphin-7 and Porcine Pancreatic Elastase",

abstract = "Mass spectrometric screening reveals that an unmodified natural heptapeptide-human beta-casomorphin-7, an internal sequence of human beta-casein that possesses opioid-like activity-reacts with porcine pancreatic elastase to form an unusually stable acyl-enzyme complex at low pH. X-ray crystallographic analysis (to 1.9 Angstrom resolution) at pH 5 shows continuous electron density linking the C-terminal isoleucine of beta-casomorphin-7 to Ser 195 through an ester bond. The structure reveals a well defined water molecule (Wat 317), equidistant between the carbon of the ester carbonyl and N epsilon 2 of His 57. Deprotonation of Wat 317 will produce a hydroxide ion positioned to attack the ester carbonyl through the favoured Burgi-Dunitz trajectory.",

keywords = "ELECTROSPRAY MASS-SPECTROMETRY, CATALYTIC WATER MOLECULE, GAMMA-CHYMOTRYPSIN, SUBSTRATE-SPECIFICITY, ALPHA-CHYMOTRYPSIN, SERINE PROTEASES, HUMAN-LEUKOCYTE, MECHANISM, INTERMEDIATE, INHIBITORS",

author = "RC Wilmouth and IJ Clifton and CV Robinson and PL Roach and RT Aplin and Westwood, {Nicholas James} and J Hajdu and CJ Schofield",

note = "Nature Structural Biology",

year = "1997",

month = jun,

language = "English",

volume = "4",

type = "Other",

}

TY - GEN

T1 - Structure of a Specific Acyl-Enzyme Complex formed between ß-Casomorphin-7 and Porcine Pancreatic Elastase

AU - Wilmouth, RC

AU - Clifton, IJ

AU - Robinson, CV

AU - Roach, PL

AU - Aplin, RT

AU - Westwood, Nicholas James

AU - Hajdu, J

AU - Schofield, CJ

N1 - Nature Structural Biology

PY - 1997/6

Y1 - 1997/6

N2 - Mass spectrometric screening reveals that an unmodified natural heptapeptide-human beta-casomorphin-7, an internal sequence of human beta-casein that possesses opioid-like activity-reacts with porcine pancreatic elastase to form an unusually stable acyl-enzyme complex at low pH. X-ray crystallographic analysis (to 1.9 Angstrom resolution) at pH 5 shows continuous electron density linking the C-terminal isoleucine of beta-casomorphin-7 to Ser 195 through an ester bond. The structure reveals a well defined water molecule (Wat 317), equidistant between the carbon of the ester carbonyl and N epsilon 2 of His 57. Deprotonation of Wat 317 will produce a hydroxide ion positioned to attack the ester carbonyl through the favoured Burgi-Dunitz trajectory.

AB - Mass spectrometric screening reveals that an unmodified natural heptapeptide-human beta-casomorphin-7, an internal sequence of human beta-casein that possesses opioid-like activity-reacts with porcine pancreatic elastase to form an unusually stable acyl-enzyme complex at low pH. X-ray crystallographic analysis (to 1.9 Angstrom resolution) at pH 5 shows continuous electron density linking the C-terminal isoleucine of beta-casomorphin-7 to Ser 195 through an ester bond. The structure reveals a well defined water molecule (Wat 317), equidistant between the carbon of the ester carbonyl and N epsilon 2 of His 57. Deprotonation of Wat 317 will produce a hydroxide ion positioned to attack the ester carbonyl through the favoured Burgi-Dunitz trajectory.

KW - ELECTROSPRAY MASS-SPECTROMETRY

KW - CATALYTIC WATER MOLECULE

KW - GAMMA-CHYMOTRYPSIN

KW - SUBSTRATE-SPECIFICITY

KW - ALPHA-CHYMOTRYPSIN

KW - SERINE PROTEASES

KW - HUMAN-LEUKOCYTE

KW - MECHANISM

KW - INTERMEDIATE

KW - INHIBITORS

UR - http://www.scopus.com/inward/record.url?scp=0031005781&partnerID=8YFLogxK

M3 - Other contribution

VL - 4

ER -

Structure of a Specific Acyl-Enzyme Complex formed between ß-Casomorphin-7 and Porcine Pancreatic Elastase

Abstract

Keywords

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