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11.
Ribonuclease Ms from Aspergillus saitoi is a small acidic protein (11 714 Da) containing 106 amino acids of known sequence. Unlike other enzymes belonging to the RNase T1 family this ribonuclease is base-unspecific. Using interactive computer graphics and energy minimisation we predicted the structure of RNase Ms on the basis of sequence homology to RNase T1 of known structure. In this report the predicted structure of this protein is presented and characterised. 相似文献
12.
Gerald D. Fasman 《Journal of biosciences》1985,8(1-2):15-23
The Chou-Fasman predictive algorithm for determining the secondary structure of proteins from the primary sequence is reviewed.
Many examples of its use are presented which illustrate its wide applicability, such as predicting (a) regions with the potential
for conformational change, (b) sequences which are capable of assuming several conformations in different environments, (c)
effects of single amino acid mutations, (d) amino acid replacements in synthesis of peptides to bring about a change in conformation,
(e) guide to the synthesis of polypeptides with definitive secondary structure,e.g. signal sequences, (f) conformational homologues from varying sequences and (g) the amino acid requirements for amphiphilicα-helical peptides. 相似文献
13.
M. Joginadha Swamy M. Venkata Krishna Sastry Avadhesha Surolia 《Journal of biosciences》1985,9(3-4):203-212
Secondary structure prediction for the 4 legume lectins: Concanavalin A, soybean agglutinin, favabean lectin and lentil lectin,
was done by the method of Chou and Fasman. This prediction shows that these four lectins fall into a structurally distinct
class of proteins, containing high amounts of β-sheet and β-turns. There is a notable similarity in the gross structure of
these proteins; all four of them contain about 40–50% of β-sheet, 35–45 % β-turn and 0–10% of α-helix. When the secondary
structure of corresponding residues in each pair of these lectins was compared, there was a striking similarity in the Concanavalin
A-soybean agglutinin and favabean lectin-lentil lectin pairs, and considerably less similarity in the other pairs, suggesting
that these legume lectins have probably evolved in a divergent manner from a common ancestor. A comparison of the predicted
potential β-turn sites also supports the hypothesis of divergent evolution in this class of lectins. 相似文献
14.
Summary DNA sequencing has revealed an internal, tandemly repetitive structure in the family of giant polypeptides encoded by three types of Balbiani ring (BR) genes, in three different species ofChironomus. Each major BR repeat can be subdivided into two halves: a region consisting of short subrepeats and a more constant region that lacks obvious subrepeats. Comparative predictions of secondary structure indicate that an -helical segment is consistently present in the amino-terminal half of the constant region in all known BR proteins. Comparative predictions, coupled with consideration of the known phosphorylation of serine and threonine residues in BR proteins, suggest that the -helical structure may also extend into the carboxy-terminal half of the constant region, possibly interrupted by -turn(s). However, it is also possible that the structure is variable, and that a -strand is present in that half in some cases. All of the constant regions conserve one methionine and one phenylalanine residue, as well as all four cysteines; these residues presumably play roles in the packing or cross-linking of aligned constant regions. The structure of the subrepeat region is not clear, but the prevalence of a tripeptide pattern (basic-proline-acidic) suggests some type of structural regularity, possibly an extended helix. The possible significance of these conserved molecular features is discussed in the context of how they may serve the elasticity, insolubility, and hydrophilicity of the fibrils and threads formed by the BR polypeptides. 相似文献
15.
杂交水稻及三系在发育过程中的酯酶同工酶比较研究 总被引:7,自引:1,他引:6
刘文芳;吴文瑜;肖翊华 《武汉植物学研究》1987,5(3):267-274
本文报道了利用聚丙烯酰胺凝胶电泳技术,测定杂交水稻及三系亲本共50个组合的萌动胚、芽,不同发育时期的叶片、根、雄蕊等12个组织或器官的酯酶同工酶的结果。根据所测结果,可把杂交水稻的酯酶同工酶酶谱分为5种类型:互补型、偏父型、偏母型、同型和“杂种”酶谱。强优势组合以互补型酶谱居多,弱优势组合都是同型酶谱,“杂种”酶谱仅见于V优64的幼穗分化期叶片和V优63、汕优63的三叶期叶片中。不同器官的互补酶谱都可作为预测杂种比势,鉴定杂交稻种子的纯度和真实性以及选配新杂交组合的一个手段或依据,但以对萌动胚或幼芽的测定更有实践意义。 相似文献
16.
Diallel analysis for sex-linked and maternal effects 总被引:40,自引:0,他引:40
J. Zhu B. S. Weir 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,92(1):1-9
Genetic models including sex-linked and maternal effects as well as autosomal gene effects are described. Monte Carlo simulations were conducted to compare efficiencies of estimation by minimum norm quadratic unbiased estimation (MINQUE) and restricted maximum likelihood (REML) methods. MINQUE(1), which has 1 for all prior values, has a similar efficiency to MINQUE(), which requires prior estimates of parameter values. MINQUE(1) has the advantage over REML of unbiased estimation and convenient computation. An adjusted unbiased prediction (AUP) method is developed for predicting random genetic effects. AUP is desirable for its easy computation and unbiasedness of both mean and variance of predictors. The jackknife procedure is appropriate for estimating the sampling variances of estimated variances (or covariances) and of predicted genetic effects. A t-test based on jackknife variances is applicable for detecting significance of variation. Worked examples from mice and silkworm data are given in order to demonstrate variance and covariance estimation and genetic effect prediction. 相似文献
17.
Abstract. One way in which a species' numbers may be estimated without direct counting is to predict their dispersion and density from more readily available habitat measures, such as landscape variables measured from maps or vegetation variables measured in the field. We compare the power of ordination and regression techniques for predicting badger ( Meles meles L.) numbers at a local scale, using a land class system, map-read landscape variables and field-derived vegetation variables. Sett density was used as a surrogate of badger density. Multiple linear regression using vegetation and landscape variables together gave the most accurate prediction of sett density, while ordination techniques were of lesser value. The addition of vegetation variables to landscape variables did not substantially improve the power of ordination. Outlier Sett Density was predicted more accurately, and by different variables, to Main Sett Density. The relationship between badger ecology and habitat variables that were useful in predicting sett density is discussed. 相似文献
18.
Mühlebach S. M. Gross M. Wirz T. Wallimann T. Perriard J. -C. Wyss M. 《Molecular and cellular biochemistry》1994,133(1):245-262
Comparisons of the protein sequences and gene structures of the known creatine kinase isoenzymes and other guanidino kinases revealed high homology and were used to determine the evolutionary relationships of the various guamidino kinases. A CK framework is defined, consisting of the most conserved sequence blocks, and diagnostic boxes are identified which are characteristic for anyone creatine kinase isoenzyme (e.g. for vertebrate B-CK) and which may serve to distinguish this isoenzyme from all others (e.g. from M-CKs and Mi-CKs). Comparison of the guanidino kinases by near-UV and far-UV circular dichroism further indicates pronounced conservation of secondary structure as well as of aromatic amino acids that are involved in catalysis.Abbreviations GuaK
guanidino kinase
- CK
creatine kinase
- B-and M-CK
brain and muscle cytosolic CK isoenzyme
- Mi-CK
mitochondrial CK isoenzyme
- ArgK
arginine kinase
- Cr
creatine
- PCr
phosphorylcreatine
- PArg
phosphorylarginine 相似文献
19.
H. -P. Piepho 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,89(5):647-654
Multilocation trials are often used to analyse the adaptability of genotypes in different environments and to find for each environment the genotype that is best adapted; i.e. that is highest yielding in that environment. For this purpose, it is of interest to obtain a reliable estimate of the mean yield of a cultivar in a given environment. This article compares two different statistical estimation procedures for this task: the Additive Main Effects and Multiplicative Interaction (AMMI) analysis and Best Linear Unbiased Prediction (BLUP). A modification of a cross validation procedure commonly used with AMMI is suggested for trials that are laid out as a randomized complete block design. The use of these procedure is exemplified using five faba bean datasets from German registration trails. BLUP was found to outperform AMMI in four of five faba bean datasets. 相似文献
20.
Summary The lipophilicity (or hydrophobicity) of amino acids is an important property relevant for protein folding and therefore of great interest in protein engineering. For peptides or peptidomimetics of potential therapeutic interest, lipophilicity is related to absorption and distribution, and thus indirectly relates to their bioactivity. A rationalization of peptide lipophilicity requires basic knowledge of the lipophilicity of the constituting amino acids. In the present contribution we will review methods to measure or calculate the lipophilicities of amino acids, including unusual amino acids, and we will make a comparison between various lipophilicity scales. 相似文献