Guamerin-Derived Synthetic Inhibitors Against Elastase and Subtilisin. Pp. 301-308.
Dong R. Kim, Seok J. Hong, Jin S. Kim, Moon K. Song and Ke W. Kang
Influence of Charge Neutraliation on the alpha-Amino pK of Aspartate Bound to Aspartate Aminotransferase. Pp. 309-314.
Khurshida Khayer, Mahmoud Akhtar, John Wilkie, David Gani, Hans Jung, Klaus D. Schnackerz, G.S. Jagannatha Rao and Paul F. Cook
A Comparative Study of the Specificity of Melittin Hydrolysis by Duodenase, Trypsin and Plasmin. Pp. 315-320.
Olga Mirgorodskaya, Galina Kazanina, Ekaterina Mirgorodskaya, Tatyana Vorotyntseva, Tatyana Zamolodchikova and Sergey Alexandrov
Molecular Organization of Citrate Synthase Extending its Quaternary Specificity. Pp. 321-328.
Huy Vinh and Claudia T. Benack Evans
Stimulation of Non-Specific Resistance by Human Casein Fragment (54-59) and its Synthetic Analogues Against Leishmania donovani Infection. Pp. 329-334.
P. Sharma, Anuradha, R. Sharon, W. Haq, B. Kundu, J.C. Katiyar and K.B. Mathur
Band 3 Aggregation in Age Separated Erythrocytes: A Relevance to Senescent Erythrocyte Recognition. Pp. 335-342.
Lana Kantor and Hiroshi Mizukami
Ubiquitin and the Ubiquitin-Like Proteins. Pp. 343-350.
Danny Casteels, Koen Kas and Jozef Merregaert
Preliminary Crystallographic Analysis of Bovine Neurophysin II Complexed with the Hormones Vasopressin and Hydrin I. Pp. 351-354.
Bing Hu, John P. Rose, Esther Breslow and Bi-Cheng Wang
[Back to top] Kinetics of Inhibition of Elastase by a Chimeric Inhibitor Containing the Reactive Site Loop from alphal-Antitrypsin. Adele J. Wolfson, Thomas R. Branham, Jennifer C. Edgoose, Adrienne K. Hammill, Kristina M. Lowe, Amy E. Spooner, Jenny Lee, Rachna Kapoor and Mingchao Shen
We have previously shown that when the 10-residue reactive-site loop from alphal-antitrypsin is placed into a turn region in intefleukin-1beta, the resulting chimeric protein retains some properties of both serpin and cytokine. The kinetic constants for interaction with elastase for a series of chimeras, containing all or part of the reactive loop have now been determined. These data suggest that hybrid proteins with an inserted loop are a useful model for investigation of the structural and sequence requirements for effective protease inhibitors.
[Back to top] Guamerin-Derived Synthetic Inhibitors Against Elastase and Subtilisin. Dong R. Kim, Seok J. Hong, Jin S. Kim, Moon K. Song and Ke W. Kang.
Two peptides ( pM and pR ) from the reactive-site region of guamerin (a leech elastase inhibitor) were synthesized. Peptide pM is identical to the sequence Thr31-Gly49 with methionine at the P1 site, peptide pR has the same sequence, but with arginine at P1. The inhibitory activities against elastase and subtilisin expressed only after oxidation in the presence of glutathiones. These results suggest that disulfide bridges between peptides is necessary for the activities of these peptides.
[Back to top] Influence of Charge Neutraliation on the alpha-Amino pK of Aspartate Bound to Aspartate Aminotransferase. Khurshida Khayer, Mahmoud Akhtar, John Wilkie, David Gani, Hans Jung,
Klaus D. Schnackerz, G.S. Jagannatha Rao and Paul F. Cook.
The pK values of the alpha-amine of aspartate and some of its analogs substituted at the alpha- and/or beta-carboxylate were measured and proton affinities calculated. Modification of the alpha-carboxylate, the beta-carboxylate, or both results in decreases in the alpha-amine pK by 1.8-2, 0.8-1.1, and 2.8-3.1 pH units, respectively, with concomitant decreases in proton affinity. Complexes in which guanidinium is hydrogen-bonded to the carboxylates of aspartate give much smaller changes in proton affinity than those observed for any of the aspartate analogs suggesting less than complete charge neutralization. The proton affinity of the alpha-amine of aspartate in Michaelis complex with aspartate aminotransferase gives a change in proton affinity consistent with a decrease of >1 but <2 pH units. Thus, although both of the carboxylates of aspartate form hydrogen-bonds to Arg-292* and Arg-386 upon binding to enzyme, charge is not completely neutralized at either of the two.
[Back to top] A Comparative Study of the Specificity of Melittin Hydrolysis by Duodenase, Trypsin and Plasmin. Olga Mirgorodskaya, Galina Kazanina, Ekaterina Mirgorodskaya, Tatyana Vorotyntseva,
Tatyana Zamolodchikova and Sergey Alexandrov.
Melittin hydrolysis by a new protease from duodenum mucosa (duodenase) was analyzed. The relationship between the chymotrypsin- and trypsin-like activities of duodenase was evaluated. Both the sites and the kinetic parameters of the duodenase-catalyzed hydrolysis were shown to differ from those of trypsinolysis and plasminolysis.
[Back to top] Molecular Organization of Citrate Synthase Extending its Quaternary Specificity. Huy Vinh and Claudia T. Benack Evans
Differences in the DNA sequence encoding citrate synthase (CS) correlates with the oligomerization and subcellular localization of the dimeric non-allosteric mitochondrial eucaryotic and hexameric allosteric procaryotic CS. An ancestral history of the nuclear CS gene was determined by PCR and DNA sequencing and shown to diverge primarily by neutral rather than adaptive mechanisms. The active site hinge peptide is rigorously conserved evolutionarily, while variable replacements occur in a unique surface beta-strand region.
[Back to top] Stimulation of Non-Specific Resistance by Human Casein Fragment (54-59) and its Synthetic Analogues Against Leishmania donovani Infection. P. Sharma, Anuradha, R. Sharon, W. Haq, B. Kundu, J.C. Katiyar and K.B. Mathur.
The prophylactic effect of human beta casein fragment (54-59) and its synthetic congeners has been studied against L. donovani infection in hamsters. Maximum parasite inhibition (84%) was observed with compound 4. The activity of this compound was further confirmed in vitro.
[Back to top] Band 3 Aggregation in Age Separated Erythrocytes: A Relevance to Senescent Erythrocyte Recognition. Lana Kantor and Hiroshi Mizukami.
We suggest that band 3 aggregation begins in the membranes of middle-aged erythrocytes causing the entire band 3 molecule to undergo conformation change as erythrocytes age. The alteration in band 3 structure exposes a previously protected proteolytic region to the cytosolic environment in the old erythrocytes, allowing a membrane bound protease to cleave at that site. Band 3 fragment is then forced to the surface of the membrane, causing such a cell to be recognized as immunologically foreign, resulting in its removal from the circulation.
[Back to top] Ubiquitin and the Ubiquitin-Like Proteins. Danny Casteels, Koen Kas and Jozef Merregaert.
Ubiquitin is an extremely conserved, small globular protein, present in all eukaryotes. The best known function of Ubiquitin is its role in targeting proteins for degradation by the S26 proteasome. Over the past years several Ubiquitin-like proteins have been reported. Up to now, 11 different proteins have been characterised, the homology with Ubiquitin ranging from 30 to 60%. Here, we present an overview of these Ubiquitin-like proteins and their relationship with Ubiquitin.
[Back to top] Preliminary Crystallographic Analysis of Bovine Neurophysin II Complexed with the Hormones Vasopressin and Hydrin I. Bing Hu, John P. Rose, Esther Breslow and Bi-Cheng Wang.
Bovine neurophysin II has been crystallized with the hormones vasopressin and hydrin I. The crystals belong to space group P41212 (or P43212) with unit cell constants of a=b=69.9A, c=222.4A and a=b=68.7A, c=l 13.8A respectively. The vasopressin complex has 4 molecules per asymmetric unit while the hydrin I complex has 2 molecules per asymmetric unit which corresponds to a solvent content of approximately 58% for both crystal forms.