EurekaMag.com logo
+ Site Statistics
References:
48,253,228
Abstracts:
22,798,842
+ Resolve Accession
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
Submit PDF Full TextSubmit PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Spectral alterations associated with the ligand promoted gross conformational change in aspartate trans carbamoylase ec 2.1.3.2


, : Spectral alterations associated with the ligand promoted gross conformational change in aspartate trans carbamoylase ec 2.1.3.2. Journal of Biological Chemistry 256(10): 4998-5004

Spectral studies on aspartate transcarbamoylase [EC 2.1.3.2] of Escherichia coli showed that the difference spectra for binding each molar equivalent of the bisubstrate analog, N-(phosphonacetyl)-L-aspartate, varied according to the degree of saturation of the 6 active sites. In contrast, the progressive binding of the same ligand to the free catalytic subunit yielded difference spectra which were independent of the extent of occupancy of the 3 active sites. These observations in conjunction with results from other physicochemical studies of the gross conformational change in the enzyme are interpreted in terms of the sum of 2 spectral changes. One represents the local effect of ligand binding and the 2nd corresponds to the conversion of the enzyme from the constrained, low affinity, T-state to a relaxes conformation of higher affinity (R-state). This transition is virtually complete when only about 4 of the 6 active sites are occupied by the bisubstrate analog. Hence, subtraction of the difference spectrum for the binding of the last 2 ligand molecules from the spectrum for binding the first 2 molecules yielded the spectral change for the conversion of about 50% of the enzyme from the T- to the R-state. A more reliable measurement of the difference spectrum corresponding to the gross conformational change of unliganded enzyme was obtained by comparing the total spectral change (local and gross) for binding ligand to all 6 active sites with the difference spectrum for binding 1.4 ligand molecules to enzyme in which 4.6 of the active sites were already occupied. Difference spectra for the assembly of enzyme from subunits in the presence and absence of the bisubstrate analog were also measured. Since the difference spectrum for binding the last 2 ligand molecules to tetraliganded aspartate transcarbamoylase was almost identical with that for ligand binding to free catalytic subunit, subtraction of the assembly difference spectrum for unliganded T-state enzyme from the reconstitution difference spectrum for liganded R-state enzyme yielded directly the difference spectrum associated with the gross conformational change in the enzyme. Despite the binding of the bisubstrate analog in all 3 approaches, the final difference spectrum corresponds to the gross conformational change in unliganded aspartate transcarbamoylase.

(PDF 0-2 workdays service)

Order PDF Full Text

Close
Close

Click here to order any other PDF Full Text


Accession: 006459369

PDF Full Text: Submit


Submit PDF Full Text

No spam - Every submission is manually reviewed

Due to poor quality, we do not accept files from Researchgate

Submitted PDF Full Texts will always be free for everyone
(We only charge for PDFs that we need to acquire)

Select a PDF file:
Close
Close

Other references

Jayawardane, G.; Russell, G.C.; Thomson, J.; Deane, D.; Cox, H.; Gatherer, D.; Ackermann, M.; Haig, D.M.; Stewart, J.P., 2008: A captured viral interleukin 10 gene with cellular exon structure. We have characterized a novel, captured and fully functional viral interleukin (IL)-10 homologue (<sub>OvHV</sub>IL-10) from the gammaherpesvirus ovine herpesvirus 2. Unlike IL-10 homologues from other gammaherpesviruses, the <sub&g...

Hoffman, P.; Jefferies, E.; Ehsan, S.; Hopper, S.; Ralph, M.A.Lambon., 2009: Selective short-term memory deficits arise from impaired domain-general semantic control mechanisms. Semantic short-term memory (STM) patients have a reduced ability to retain semantic information over brief delays but perform well on other semantic tasks; this pattern suggests damage to a dedicated buffer for semantic information. Alternatively,...

Szymanski R.L.; Baust J.G., 1990: Multiple exponential analysis of nuclear magnetic relaxation in biological systems estimating low temperature tissue damage. Cryobiology 27(6): 673

Moisescu V., 1981: Oligocene deposits of Transylvania and their correlation in Paratethys. Revue Roumaine de Geologie, Geophysique et Geographie, Serie de Geologie 25(1): 161-169

Pcelincev, V., 1927: The Jurassic and Lower Cretaceous fauna of the Crimea and Caucasus. (Russian) English Abstracts pp. 25, 61, 112, 135, 147, 176, 188, 219, 246, 258. Memoires du Comite Geologique Leningrad NS: 172 i-xvi

Apol skiy O.P.; Grigaytis R.K., 1994: Riphean deposits in Kazakhstan and their correlation with the Caledonides. Regional'naya Geologiya i Metallogeniya 1994(3): 42-58

Moser, Fanny., 1908: Japanische Ctenophoren. (Beitrage zur Naturgeschichte Ostasiens. Hrsg. von F, Doflein. Abh. 4.). Munchen Abh Ak Wiss math-phys Kl Suppl-Bd, 1 1-78

Shields, J.A.; Augsburger, J.J.; Sanborn, G.E.; Klein, R.M., 1983: Adenoma of the iris-pigment epithelium. An 11-year-old boy was noted to have a multinodular tumor involving the peripheral iris and trabecular meshwork in his left eye. During the next 12 years, the lesion slowly enlarged and produced pigmentary dispersion in the anterior chamber and gl...

S.G.lais, C.; Kim, S.Hee.; Ding, L.; Yount, J.; Ivanov, D.; Spearman, P.; Wu, L., 2016: A Putative Cyclin-binding Motif in Human SAMHD1 Contributes to Protein Phosphorylation, Localization and Stability. NlmCategory="UNASSIGNED">Sterile alpha motif and HD domain-containing protein 1 (SAMHD1) is a mammalian protein that regulates intracellular dNTP levels through its hydrolysis of dNTPs. SAMHD1 functions as an important retroviral rest...

Solbu, T.Tallak.; Bjørkmo, M.; Berghuis, P.; Harkany, T.; Chaudhry, F.A., 2010: SAT1, A Glutamine Transporter, is Preferentially Expressed in GABAergic Neurons. Subsets of GABAergic neurons are able to maintain high frequency discharge patterns, which requires efficient replenishment of the releasable pool of GABA. Although glutamine is considered a preferred precursor of GABA, the identity of transporter...