Unlike the Quaternary Structure Transition, the Tertiary Structure Change of the 240s Loop in Allosteric Aspartate Transcarbamylase Requires Active Site Saturation by Substrate for Completion

Biochemistry ◽  
1995 ◽  
Vol 34 (48) ◽  
pp. 15654-15660 ◽  
Author(s):  
Luc Fetler ◽  
Patrice Vachette ◽  
Guy Herve ◽  
Moncef M. Ladjimi
Keyword(s):  
Active Site ◽  
Tertiary Structure ◽  
Quaternary Structure ◽  
Structure Change ◽  
Aspartate Transcarbamylase ◽  
Structure Transition ◽  
Site Saturation

Kinetics of the Quaternary Structure Change of Aspartate Transcarbamylase Triggered by Succinate, a Competitive Inhibitor

Biochemistry ◽  
1994 ◽  
Vol 33 (33) ◽  
pp. 10007-10012 ◽  
Author(s):  
Hirotsugu Tsuruta ◽  
Patrice Vachette ◽  
Takayuki Sano ◽  
Michael F. Moody ◽  
Yoshiyuki Amemiya ◽  
...  
Keyword(s):  
Quaternary Structure ◽  
Competitive Inhibitor ◽  
Structure Change ◽  
Aspartate Transcarbamylase ◽  
Kinetics Of

Influence of Nucleotide Effectors on the Kinetics of the Quaternary Structure Transition of Allosteric Aspartate Transcarbamylase

2005 ◽  
Vol 348 (1) ◽  
pp. 195-204 ◽  
Author(s):  
Hiro Tsuruta ◽  
Hiroshi Kihara ◽  
Takayuki Sano ◽  
Yoshiyuki Amemiya ◽  
Patrice Vachette
Keyword(s):  
Quaternary Structure ◽  
Aspartate Transcarbamylase ◽  
Structure Transition ◽  
Kinetics Of

scholarly journals Chemical modification of serine at the active site of penicillin acylase from Kluyvera citrophila

1991 ◽  
Vol 280 (3) ◽  
pp. 659-662 ◽  
Author(s):  
J Martín ◽  
A Slade ◽  
A Aitken ◽  
R Arche ◽  
R Virden
Keyword(s):  
Active Site ◽  
Tertiary Structure ◽  
Thiol Group ◽  
Iodoacetic Acid ◽  
Penicillin Acylase ◽  
Protein Product ◽  
Side Chain ◽  
Serine Residue ◽  
Conserved Sequence ◽  
Ester Substrate

The site of reaction of penicillin acylase from Kluyvera citrophila with the potent inhibitor phenylmethanesulphonyl fluoride was investigated by incubating the inactivated enzyme with thioacetic acid to convert the side chain of the putative active-site serine residue to that of cysteine. The protein product contained one thiol group, which was reactive towards 2,2′-dipyridyl disulphide and iodoacetic acid. Carboxymethylcysteine was identified as the N-terminal residue of the beta-subunit of the carboxy[3H]methylthiol-protein. No significant changes in tertiary structure were detected in the modified penicillin acylase using near-u.v. c.d. spectroscopy. However, the catalytic activity (kcat) with either an anilide or an ester substrate was decreased in the thiol-protein by a factor of more than 10(4). A comparison of sequences of apparently related acylases shows no other extensive regions of conserved sequence containing an invariant serine residue. The side chain of this residue is proposed as a candidate nucleophile in the formation of an acyl-enzyme during catalysis.

scholarly journals Evidence from 13C NMR for protonation of carbamyl-P and N-(phosphonacetyl)-L-aspartate in the active site of aspartate transcarbamylase.

1976 ◽  
Vol 251 (19) ◽  
pp. 5976-5985 ◽  
Author(s):  
M F Roberts ◽  
S J Opella ◽  
M H Schaffer ◽  
H M Phillips ◽  
G R Stark
Keyword(s):  
13C Nmr ◽  
Active Site ◽  
Aspartate Transcarbamylase

The crystal structure of human mitochondrial 3-ketoacyl-CoA thiolase (T1): insight into the reaction mechanism of its thiolase and thioesterase activities

2014 ◽  
Vol 70 (12) ◽  
pp. 3212-3225 ◽  
Author(s):  
Tiila-Riikka Kiema ◽  
Rajesh K. Harijan ◽  
Malgorzata Strozyk ◽  
Toshiyuki Fukao ◽  
Stefan E. H. Alexson ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Reaction Mechanism ◽  
Active Site ◽  
Quaternary Structure ◽  
Fatty Acyl ◽  
Physiological Importance ◽  
Loop Domain ◽  
Solution Studies ◽  
Hydrolysis Of ◽  
Insight Into

Crystal structures of human mitochondrial 3-ketoacyl-CoA thiolase (hT1) in the apo form and in complex with CoA have been determined at 2.0 Å resolution. The structures confirm the tetrameric quaternary structure of this degradative thiolase. The active site is surprisingly similar to the active site of theZoogloea ramigerabiosynthetic tetrameric thiolase (PDB entries 1dm3 and 1m1o) and different from the active site of the peroxisomal dimeric degradative thiolase (PDB entries 1afw and 2iik). A cavity analysis suggests a mode of binding for the fatty-acyl tail in a tunnel lined by the Nβ2–Nα2 loop of the adjacent subunit and the Lα1 helix of the loop domain. Soaking of the apo hT1 crystals with octanoyl-CoA resulted in a crystal structure in complex with CoA owing to the intrinsic acyl-CoA thioesterase activity of hT1. Solution studies confirm that hT1 has low acyl-CoA thioesterase activity for fatty acyl-CoA substrates. The fastest rate is observed for the hydrolysis of butyryl-CoA. It is also shown that T1 has significant biosynthetic thiolase activity, which is predicted to be of physiological importance.

scholarly journals Structural comparisons lead to the definition of a new superfamily of NAD(P)(H)-accepting oxidoreductases: the single-domain reductases/epimerases/dehydrogenases (the ‘RED’ family)

1994 ◽  
Vol 304 (1) ◽  
pp. 95-99 ◽  
Author(s):  
G Labesse ◽  
A Vidal-Cros ◽  
J Chomilier ◽  
M Gaudry ◽  
J P Mornon
Keyword(s):  
Amino Acids ◽  
Sequence Alignment ◽  
Active Site ◽  
Tertiary Structure ◽  
Binding Specificity ◽  
Single Domain ◽  
Divergent Evolution ◽  
Cofactor Binding ◽  
Sequence Identity ◽  
Definition Of

Using both primary- and tertiary-structure comparisons, we have established new structural similarities shared by reductases, epimerases and dehydrogenases not previously known to be related. Despite the low sequence identity (down to 10%), short consensus segments are identified. We show that the sequence, the active site and the supersecondary structure are well conserved in these proteins. New homologues (the protochlorophyllide reductases) are detected, and we define a new superfamily composed of single-domain dinucleotide-binding enzymes. Rules for the cofactor-binding specificity are deduced from our sequence alignment. The involvement of some amino acids in catalysis is discussed. Comparison with two-domain dehydrogenases allows us to distinguish two general mechanisms of divergent evolution.

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