Hard α-Keratin Intermediate Filament Chains: Substructure of the N- and C-Terminal Domains and the Predicted Structure and Function of the C-Terminal Domains of Type I and Type II Chains

1998 ◽  
Vol 122 (1-2) ◽  
pp. 67-75 ◽  
Author(s):  
David A.D Parry ◽  
A.C.T North
Keyword(s):  
Intermediate Filament ◽  
Structure And Function ◽  
Type I ◽  
Type Ii ◽  
And Function ◽  
Terminal Domains

scholarly journals Biosynthesis of Polyketides in Streptomyces

2019 ◽  
Vol 7 (5) ◽  
pp. 124 ◽  
Author(s):  
Chandra Risdian ◽  
Tjandrawati Mozef ◽  
Joachim Wink
Keyword(s):  
Secondary Metabolites ◽  
Structure And Function ◽  
Polyketide Synthases ◽  
Type I ◽  
Type Ii ◽  
Filamentous Form ◽  
Gram Positive Bacteria ◽  
Wide Range ◽  
Different Types ◽  
And Function

Polyketides are a large group of secondary metabolites that have notable variety in their structure and function. Polyketides exhibit a wide range of bioactivities such as antibacterial, antifungal, anticancer, antiviral, immune-suppressing, anti-cholesterol, and anti-inflammatory activity. Naturally, they are found in bacteria, fungi, plants, protists, insects, mollusks, and sponges. Streptomyces is a genus of Gram-positive bacteria that has a filamentous form like fungi. This genus is best known as one of the polyketides producers. Some examples of polyketides produced by Streptomyces are rapamycin, oleandomycin, actinorhodin, daunorubicin, and caprazamycin. Biosynthesis of polyketides involves a group of enzyme activities called polyketide synthases (PKSs). There are three types of PKSs (type I, type II, and type III) in Streptomyces responsible for producing polyketides. This paper focuses on the biosynthesis of polyketides in Streptomyces with three structurally-different types of PKSs.

Dimeric/oligomeric DNA methyltransferases: an unfinished story

2009 ◽  
Vol 390 (9) ◽  
Author(s):  
Ernst G. Malygin ◽  
Alexey A. Evdokimov ◽  
Stanley Hattman
Keyword(s):  
Experimental Data ◽  
Dna Methyltransferases ◽  
Structure And Function ◽  
Type I ◽  
Type Ii ◽  
Kinetic Characteristics ◽  
Biological Substrate ◽  
Oligomeric Dna ◽  
And Function

Abstract DNA methyltransferases (MTases) are enzymes that carry out post-replicative sequence-specific modifications. The initial experimental data on the structure and kinetic characteristics of the EcoRI MTase led to the paradigm that type II systems comprise dimeric endonucleases and monomeric MTases. In retrospect, this was logical because, while the biological substrate of the restriction endonuclease is two-fold symmetrical, the in vivo substrate for the MTase is generally hemi-methylated and, hence, inherently asymmetric. Thus, the paradigm was extended to include all DNA MTases except the more complex bifunctional type I and type III enzymes. Nevertheless, a gradual enlightenment grew over the last decade that has changed the accepted view on the structure of DNA MTases. These results necessitate a more complex view of the structure and function of these important enzymes.

scholarly journals Biosynthesis of Polyketides in Streptomyces

2018 ◽  
Author(s):  
Chandra Risdian
Keyword(s):  
Secondary Metabolites ◽  
Structure And Function ◽  
Polyketide Synthases ◽  
Type I ◽  
Type Ii ◽  
Filamentous Form ◽  
Gram Positive Bacteria ◽  
Wide Range ◽  
Different Types ◽  
And Function

Polyketides are large group of secondary metabolites that have notable variety in their structure and function. Polyketides exhibit a wide range of bioactivities such as antibacterial, antifungal, anticancer, antiviral, immune-suppressing, anti-cholesterol and anti-inflammatory activity. Naturally, they are found in bacteria, fungi, plants, protists, insects, mollusks and sponges. Streptomyces is a genus of Gram-positive bacteria that has a filamentous form like fungi. This genus is best known as one of polyketides producers. Some examples of polyketides produced by Streptomyces are rapamycin, oleandomycin, actinorhodin, daunorubicin and caprazamycin. Biosynthesis of polyketides involves a group of enzyme activities called polyketide synthases (PKSs). There are three types of PKSs (type I, type II, and type III) in Streptomyces that responsible for producing polyketides. This paper focuses on biosynthesis of polyketides in Streptomyces with three structurally different types of PKSs.

The beaded filament of the eye lens: an unexpected key to intermediate filament structure and function

1996 ◽  
Vol 6 (4) ◽  
pp. 123-126 ◽  
Author(s):  
Roy A. Quinlan ◽  
Jane M. Carte ◽  
Aileen Sandilands ◽  
Alan R. Prescott
Keyword(s):  
Intermediate Filament ◽  
Structure And Function ◽  
Eye Lens ◽  
Filament Structure ◽  
And Function

Genes for intermediate filament proteins and the draft sequence of the human genome

2001 ◽  
Vol 114 (14) ◽  
pp. 2569-2575 ◽  
Author(s):  
Michael Hesse ◽  
Thomas M. Magin ◽  
Klaus Weber
Keyword(s):  
Human Genome ◽  
Dna Sequences ◽  
Intermediate Filament ◽  
Muscle Protein ◽  
Gene Families ◽  
Type I ◽  
Type Ii ◽  
Draft Sequence ◽  
Intermediate Filament Proteins ◽  
Processed Pseudogenes

We screened the draft sequence of the human genome for genes that encode intermediate filament (IF) proteins in general, and keratins in particular. The draft covers nearly all previously established IF genes including the recent cDNA and gene additions, such as pancreatic keratin 23, synemin and the novel muscle protein syncoilin. In the draft, seven novel type II keratins were identified, presumably expressed in the hair follicle/epidermal appendages. In summary, 65 IF genes were detected, placing IF among the 100 largest gene families in humans. All functional keratin genes map to the two known keratin clusters on chromosomes 12 (type II plus keratin 18) and 17 (type I), whereas other IF genes are not clustered. Of the 208 keratin-related DNA sequences, only 49 reflect true keratin genes, whereas the majority describe inactive gene fragments and processed pseudogenes. Surprisingly, nearly 90% of these inactive genes relate specifically to the genes of keratins 8 and 18. Other keratin genes, as well as those that encode non-keratin IF proteins, lack either gene fragments/pseudogenes or have only a few derivatives. As parasitic derivatives of mature mRNAs, the processed pseudogenes of keratins 8 and 18 have invaded most chromosomes, often at several positions. We describe the limits of our analysis and discuss the striking unevenness of pseudogene derivation in the IF multigene family. Finally, we propose to extend the nomenclature of Moll and colleagues to any novel keratin.

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