Summary

Translation initiation factor 1A / IF-1

This family includes both the eukaryotic translation factor eIF-1A and the bacterial translation initiation factor IF-1.

Literature references

Kyrpides NC, Woese CR; , Proc Natl Acad Sci U S A 1998;95:224-228.: Universally conserved translation initiation factors. PUBMED:9419357

InterPro entry IPR006196

The S1 domain of around 70 amino acids, originally identified in ribosomal protein S1, is found in a large number of RNA-associated proteins. It has been shown that S1 proteins bind RNA through their S1 domains with some degree of sequence specificity. This type of S1 domain is found in translation initiation factor 1.

The solution structure of one S1 RNA-binding domain from Escherichia coli polynucleotide phosphorylase has been determined PUBMED:9008164. It displays some similarity with the cold shock domain (CSD) (). Both the S1 and the CSD domain consist of an antiparallel beta barrel of the same topology with 5 beta strands. This fold is also shared by many other proteins of unrelated function and is known as the OB fold. However, the S1 and CSD fold can be distinguished from the other OB folds by the presence of a short 3(10) helix at the end of strand 3. This unique feature is likely to form a part of the DNA/RNA-binding site.

More information about these proteins can be found at Protein of the Month: RNA Exosomes PUBMED:.

Clan

This family is a member of clan OB (CL0021), which contains the following 32 members:

BOF CSD DNA_ligase_OB DUF2110 DUF223 DUF35 EFP eIF-1a eIF-5a EutN_CcmL EXOSC1 mRNA_cap_C OB_RNB Phage_DNA_bind Rep-A_N Rep_fac-A_3 Rho_RNA_bind Ribosomal_L2 Ribosomal_S12 Ribosomal_S17 RNA_pol_Rbc25 RNA_pol_Rpb8 RuvA_N S1 SSB Stn1 Telo_bind TOBE TOBE_2 TRAM tRNA_anti tRNA_bind

Gene Ontology

Molecular function	translation initiation factor activity (GO:0003743)
Molecular function	RNA binding (GO:0003723)
Biological process	translational initiation (GO:0006413)

Internal database links

SCOOP:

ATP-synt_ab_C PTS_IIB DUF2075 DUF2202

External database links

PANDIT:	PF01176
PROSITE:	PDOC00970
SCOP:	1d7q
SYSTERS:	eIF-1a

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Alignments

There are various ways to view or download the sequence alignments that we store. You can use a sequence viewer to look at either the seed or full alignment for the family, or you can look at a plain text version of the sequence in a variety of different formats. More...

View options

Alignment:	Seed (64) Full (2260) NCBI (3918) Metagenomics (2073)
Viewer:

Formatting options

Alignment:	Seed (64) Full (2260)
Format:
Order:	Tree Alphabetical
Sequence:	Inserts lower case All upper case
Gaps:
Download/view:	Download View

Download options

Very large alignments can often cause problems for the formatting tool above. If you find that downloading or viewing a large alignment is problematic, you can also download a gzip-compressed, Stockholm-format file containing the seed or full alignment for this family.

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

The main seed and full alignments are generated using sequences from the UniProt sequence database. However, we also generate alignments using sequences from the NCBI sequence database and the "metaseq" metagenomics dataset.

You can view alignments from these two additional datasets using the form above, or you can download alignments of NCBI or metagenomics sequences, as gzip-compressed files.

Pfam alignments:	Seed (64) Full (2260) NCBI (3918) Metagenomics (2073)
Full length sequences	Full-sequences (2260)

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER2.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...

Trees

This page displays the phylogenetic tree for this family. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed or full alignments.

Note: You can also download the data files for the seed, full, NCBI or metagenomics trees.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation

Seed source:

Prosite

Previous IDs:

none

Type:

Domain

Author:

Finn RD, Bateman A, Mistry J, Wood V

Number in seed:

64

Number in full:

2260

Average length of the domain:

65.50 aa

Average identity of full alignment:

48 %

Average coverage of the sequence by the domain:

74.32 %

HMM information

HMM build commands:

build method: hmmbuild -o /dev/null HMM SEED

search method: hmmsearch -Z 9421015 -E 1000 HMM pfamseq

Model details:

Parameter	Sequence	Domain
Gathering cut-off	23.0	23.0
Trusted cut-off	23.2	24.2
Noise cut-off	22.9	22.9

Model length:

65

Family (HMM) version:

12

Download:

download the raw HMM for this family

Species distribution

Tree controls

Hide

The tree shows the occurrence of this domain across different species. More...

Species trees

We show the species tree in one of two ways. For smaller trees we try to show an interactive representation, which allows you to select specific nodes in the tree and view them as an alignment or as a set of Pfam domain graphics.

Unfortunately we have found that there are problems viewing the interactive tree when the it becomes larger than a certain limit. Furthermore, we have found that Internet Explorer can become unresponsive when viewing some trees, regardless of their size. We therefore show a text representation of the species tree when the size is above a certain limit or if you are using Internet Explorer to view the site.

If you are using IE you can still load the interactive tree by clicking the "Generate interactive tree" button, but please be aware of the potential problems that the interactive species tree can cause.

Interactive tree

For all of the domain matches in a full alignment, we count the number that are found on all sequences in the alignment. This total is shown in the purple box.

We also count the number of unique sequences on which each domain is found, which is shown in green. Note that a domain may appear multiple times on the same sequence, leading to the difference between these two numbers.

Finally, we group sequences from the same organism according to the NCBI code that is assigned by UniProt, allowing us to count the number of distinct sequences on which the domain is found. This value is shown in the pink boxes.

We use the NCBI species tree to group organisms according to their taxonomy and this forms the structure of the displayed tree. Note that in some cases the trees are too large (have too many nodes) to allow us to build an interactive tree, but in most cases you can still view the tree in a plain text, non-interactive representation. Those species which are represented in the seed alignment for this domain are highlighted.

You can use the tree controls to manipulate how the interactive tree is displayed:

show/hide the summary boxes
highlight species that are represented in the seed alignment
expand/collapse the tree or expand it to a given depth
select a sub-tree or a set of species within the tree and view them graphically or as an alignment
save a plain text representation of the tree

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Structures

For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the eIF-1a domain has been found.

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Family: eIF-1a (PF01176)

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