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Anopheles Gambiae Purine Nucleoside Phosphorylase: Catalysis, Structure And Inhibition, Erika Taylor, Agnes Rinaldo-Matthis, Lei Li, Mahmoud Ghanem, Keith Hazleton, M. Belen Cassera, Steven Almo, Vern Schramm Oct 2007

Anopheles Gambiae Purine Nucleoside Phosphorylase: Catalysis, Structure And Inhibition, Erika Taylor, Agnes Rinaldo-Matthis, Lei Li, Mahmoud Ghanem, Keith Hazleton, M. Belen Cassera, Steven Almo, Vern Schramm

Erika A. Taylor, Ph.D.

The purine salvage pathway of Anopheles gambiae, a mosquito that transmits malaria, has been identified in genome searches on the basis of sequence homology with characterized enzymes. Purine nucleoside phosphorylase (PNP) is a target for the development of therapeutic agents in humans and purine auxotrophs, including malarial parasites. The PNP from Anopheles gambiae (AgPNP) was expressed in Escherichia coli and compared to the PNPs from Homo sapiens (HsPNP) and Plasmodium falciparum (PfPNP). AgPNP has kcat values of 54 and 41 s-1 for 2'-deoxyinosine and inosine, its preferred substrates, and 1.0 s-1 for guanosine. However, the chemical step is fast for …


Effects Of Angiotensin 1-7 On The Actions Of Angiotensin Ii In The Renal And Mesenteric Vasculature Of Hypertensive And Streptozotocin-Induced Diabetic Rats, Mohd Rais Mustafa, Murugan Dharmani, Francis I. Achike, Meng-Kwoon Sim Apr 2007

Effects Of Angiotensin 1-7 On The Actions Of Angiotensin Ii In The Renal And Mesenteric Vasculature Of Hypertensive And Streptozotocin-Induced Diabetic Rats, Mohd Rais Mustafa, Murugan Dharmani, Francis I. Achike, Meng-Kwoon Sim

Mohd Rais Mustafa

Angiotensin 1-7, a heptapeptide derived from metabolism of either angiotensin I or angiotensin II, is a biologically active peptide of the renin–angiotensin system. The present study investigated the effect of angiotensin 1-7 on the vasopressor action of angiotensin II in the renal and mesenteric vasculature of Wistar-Kyoto (WKY) rats, spontaneously hypertensive rats (SHR) and streptozotocin-induced diabetic rats. Angiotensin II-induced dose-dependent vasoconstrictions in the renal vasculature. The pressor response was enhanced in the SHR and reduced in the streptozotocin-diabetic rat compared to WKY rats. Angiotensin 1-7 attenuated the angiotensin II pressor responses in the renal vasculature of WKY and SHR rats. …


Ethnic Variations In Paraoxonase1 Polymorphism In The Malaysian Population, Rozaida @ Poh Yuen Ying Jan 2007

Ethnic Variations In Paraoxonase1 Polymorphism In The Malaysian Population, Rozaida @ Poh Yuen Ying

Rozaida @ Poh Yuen Ying

The role of high-density lipoprotein associated paraoxonase (PON) 1 in protection against oxidative stress associated with the development of complications in diabetes mellitus has been reported. Variations in the PON1 gene, 55LM and 192QR have been described in different populations. These variations are known to be risk factors for heart disease, especially the L and R alleles. We have investigated the prevalence of both polymorphisms in the Malaysian population comprising the three major ethnic groups: Malay, Chinese and Indian, using polymerase chain reaction followed by restriction endonuclease digestion. The results show the pooled frequencies of L and R alleles were …


Modulation Of Vascular Reactivity In Normal, Hypertensive And Diabetic Rat Aortae By A Non-Antioxidant Flavonoid, Mohd Rais Mustafa, Macha Ajay, Fracis I. Achike Jan 2007

Modulation Of Vascular Reactivity In Normal, Hypertensive And Diabetic Rat Aortae By A Non-Antioxidant Flavonoid, Mohd Rais Mustafa, Macha Ajay, Fracis I. Achike

Mohd Rais Mustafa

In this study, we report the effects of a non-antioxidant flavonoid flavone on vascular reactivity in Wistar–Kyoto (WKY) rat isolated aortae. Whether flavone directly modulates vascular reactivity in spontaneously hypertensive rat (SHR) and streptozotocin-induced diabetic-WKY rat isolated aortae was also determined. Thoracic aortic rings were mounted in organ chambers and exposed to various drug treatments in the presence of flavone or its vehicle (DMSO), which served as control. Pretreatment with flavone enhanced relaxant effects to endothelium-dependent vasodilator acetylcholine (ACh) and attenuated contractile effects to 1-receptor agonist phenylephrine (PE) in WKY aortae compared to those observed in control aortic rings. Flavone …


Structure And Thermodynamics Of A Conserved U2 Snrna Domain From Yeast And Human, Dipali G. Sashital, Vincenzo Venditti, Courtney G. Angers, Gabriel Cornilescu, Samuel E. Butcher Jan 2007

Structure And Thermodynamics Of A Conserved U2 Snrna Domain From Yeast And Human, Dipali G. Sashital, Vincenzo Venditti, Courtney G. Angers, Gabriel Cornilescu, Samuel E. Butcher

Vincenzo Venditti

The spliceosome is a dynamic ribonucleoprotein complex responsible for the removal of intron sequences from pre-messenger RNA. The highly conserved 5′ end of the U2 small nuclear RNA (snRNA) makes key base-pairing interactions with the intron branch point sequence and U6 snRNA. U2 stem I, a stem–loop located in the 5′ region of U2, has been implicated in spliceosome assembly and may modulate the folding of the U2 and U6 snRNAs in the spliceosome active site. Here we present the NMR structures of U2 stem I from human and Saccharomyces cerevisiae. These sequences represent the two major classes of U2 …