biology

T-A hol family

T-A hol family is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand T-A hol family rather than just read about it. In short: The Putative 3-4 TMS Transglycosylase-associated Holin (T-A Hol) Family (TC# 1.E.43) is believed to be a group of holins that does not belong to one of the seven holin superfamilies. Homologues include thousands of diverse phage and bacterial proteins between 80 and 140 amino acyl residues (aas) in length that exhibit 3 to 4 transmembrane segments (TMSs).

Key takeaways

T-A hol family belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect T-A hol family to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of T-A hol family from memory before moving on to harder problems.

Reference excerpt

The Putative 3-4 TMS Transglycosylase-associated Holin (T-A Hol) Family (TC# 1.E.43) is believed to be a group of holins that does not belong to one of the seven holin superfamilies. Homologues include thousands of diverse phage and bacterial proteins between 80 and 140 amino acyl residues (aas) in length that exhibit 3 to 4 transmembrane segments (TMSs). These proteins are holin-like in their size and topology and are designated 'Transglycosylase-associated', 'Putative holin', 'Phage-like transmembrane protein', 'YeaQ protein', etc. in the NCBI protein database. As of early 2016, they remain functionally uncharacterized. They derive from a wide range of bacterial and archaeal phyla including both Gram-negative and Gram-positive bacteria. These proteins are related to the RDD family (TC# 9.B.45) in the conserved domain database. A representative list of proteins belonging to the T-A Hol family can be found in the Transporter Classification Database.

See also Holin Lysin Transporter Classification Database

Further reading Reddy, BL; Saier, MH (2013). "Topological and phylogenetic analyses of bacterial holin families and superfamilies". Biochim. Biophys. Acta. 1828 (11): 2654–71. doi:10.1016/j.bbamem.2013.07.004. PMC 3788059. PMID 23856191.. Saier, MH; Reddy, BL (2015). "Holins in bacteria, eukaryotes, and archaea: multifunctional xenologues with potential biotechnological and biomedical applications". J. Bacteriol. 197 (1): 7–17. doi:10.1128/JB.02046-14. PMC 4288690. PMID 25157079.. Wang, IN; Smith, DL; Young, R (2000). "Holins: the protein clocks of bacteriophage infections". Annu. Rev. Microbiol. 54: 799–825. doi:10.1146/annurev.micro.54.1.799. PMID 11018145.. Young, R; Bläsi, U (1995). "Holins: form and function in bacteriophage lysis". FEMS Microbiol. Rev. 17 (1–2): 191–205. doi:10.1111/j.1574-6976.1995.tb00202.x. PMID 7669346..

References

As of this edit, this article uses content from "1.E.43 Putative 3-4 TMS Transglycosylase-associated Holin (T-A Hol) Family", which is licensed in a way that permits reuse under the Creative Commons Attribution-ShareAlike 3.0 Unported License, but not under the GFDL. All relevant terms must be followed.

Worked examples

Example 1 — a first encounter with T-A hol family

Start with the simplest possible case. Write down what T-A hol family claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to T-A hol family before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about T-A hol family ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of T-A hol family

In research: T-A hol family appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses T-A hol family in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: T-A hol family is common in secondary-school and first-year university syllabi. It links to neighbouring topics Holins, Integral membrane proteins, Membrane proteins, so understanding it makes those chapters shorter.
In everyday life: Look for T-A hol family outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study T-A hol family in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what T-A hol family means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain T-A hol family out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is T-A hol family in simple terms?

Why does T-A hol family matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study T-A hol family?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on T-A hol family.